TRTW

<a href="https://forums.audiworld.com/a4/msgs/2589867.phtml">Using the LCD Repair Kit from Circuit Solutions to fix your climate control display</a>

Nate (ETKA+Scumbag)

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bassed-ndzmorezone5

German Auto Parts at insanely good prices!<ul><li><a href="http://pap-parts.com/default.asp">PAP-PARTS</a></li></ul>

starting ...

This is how I did it but there are tons of other ways to do everything
How To Paint Your B5 A4:

This write-up will focus around what I think is the best way to repaint a car a different color. Also this is mainly for a b5 although most of the steps can be followed for painting anything.

Disclaimer: I take no responsibility for any damage done to your car or yourself.

Safety First: Painting a car can be very dangerous to your respiratory system. You must combat the dust of sanding, chemicals on your hands and the fumes. I suggest a mask when doing any type of sanding particularly machine sanding. I also suggest looking into a breathing machine setup if you plan to do any amount of painting.

Paint:
I prefer to use PPG products. In this and all my write-ups I will go by their specifications. I am using their Deltron paint line throughout.


And finally here is how I repainted my car.

Step 1 Cleaning:
Before beginning to sand anything wash the surface thoroughly with water and dish washing soap. I have found the simplest soaps to be the best. One's with foaming actions or degreasing action tend to leave a residue. Once dry wipe down everything with a prep spray or diluted rubbing alcohol. This is done to remove dirt, grease, and wax from the surface. If not done you risk sanding the containments into the paint and getting fisheyes as well as other problems with your paint. You must get everything clean before you begin sanding.

Step 2 Disassembly:
Because I am changing the color of the car I wanted to paint everything I could off the car. You could do this differently by masking off, painting the jams, remaking, and painting the outside. I removed all door cards, windows, trunk interior, weather-stripping, door clasps, and whatever else was in my way. When you open my door everything is the same color.
<img src="http://img.photobucket.com/albums/v110/hampp2/8f3f5896.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/7fa09cd4.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/116558c4.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/8f9a144c.jpg">
Step 2 Bodywork:
Now you can begin sanding. What you plan to do will determine what grit to use. For the car, I did body work in several spots.

Shaving Middle Door Moldings:
To shave these you first pull the them off they car. They are held by double sided tape. I removed what was left by using a rubber eraser wheel on an electric drill. I then grinded the spots to bare metal where I was going to weld. With the smaller holes I just filled them in with weld and grinded them smooth. With the bigger holes I made a patch and I welded them in. I used a small gasless mig welder to do this.
<img src="http://img.photobucket.com/albums/v110/hampp2/a1b6bdc6.jpg">
Lower Door Moldings:
I pulled these off using vice grips. I then grinded the existing weld/pin smooth. On the ones where there was a hole left I filled in the hole with weld.
<img src="http://img.photobucket.com/albums/v110/hampp2/3cd38746.jpg">
Shaving the Lower Line on the Trunk:
To do this I grinded the area to bare metal. I then was able to run a bead of weld across the panel. I went slowly to be carefully not to warp the metal. You can probably get away with just using filler on this.
<img src="http://img.photobucket.com/albums/v110/hampp2/3c41a3fa.jpg">
Fixing Dings and Dents:
I had a dent on my rear quarter panel. It was small enough that I did not feel the need to pull it before I filled it. However before putting filler on you want to knock down the metal around the dent. When a dent happens it pushes the metal in the center in and the area around the dent out to form a crown.
<img src="http://img.photobucket.com/albums/v110/hampp2/867773a9.jpg">
Rolling Fenders:
I filled the holes in the fender where trim used to be with patches. I then pulled the fenders off the car and used a hammer and dolly to roll them. You do not have to be careful about chipping paint at this point. You must make sure that you do not create a wave in the fender though.

Using Filler:
Filler is not bad stuff. You want to keep it to as thin a layer as possible and make sure that you sand the area with the right grit sand paper so you have the tooth the filler needs to hold. I do not like Bondo products. All the filler I used was a Rage product. Once I had the welds and dents smooth by sanding I hit the areas around them with 40 or 60 grit sandpaper. You must extend the area beyond just where you feel the imperfections. I then used Rage Extreme filler on all the dents. To level filler you can use what looks like a cheese grater. The longer the board, the straighter the panel. I used 120 grit sandpaper to begin to form the filler. You work up in grit as you get closer to having a flat surface. So when sanding you want to use the longest board possible. Over the filler I used a metal glaze which is a lot thinner and helps to fill in any pinholes. Using a guide coat helps you to see when everything is level and if there are any low spots. You should not have any pinholes and it should feel basically perfect when done. Primer is not going to level out a surface.

Sanding the rest of the car:
I used 320 grit on a da sander to reach what I could. I know the write-up is out of order but I did this after the first stage of filler. I then cleaned the car very well. I finished the filler work and then sanded by hand with 400 everything I couldn't reach with the da. At this point the car was ready for primer.

PAINT WILL NOT STICK TO SHINEY SPOTS

Prepping for paint:
I took my trunk, hood, fenders, and doors off the car for paint. I mentioned earlier on the other way to do this. This was the best way for me. I also am not painting any plastic parts at this point. You want to spray parts as they would lie on the car. I was not able to do this due to space.

Primer:
Before primer I took a nylon pad to every curvy part of the car that did not get sanded well with sandpaper. Then the car got washed once again. After the car is dried it was cleaned with a prep spray and then with a diluted rubbing alcohol and water spray. At this point you are able begin mixing paint. I am only going to spray the portions I did body work to. You must extend your paint area each coat however.

Primer Ready to Spray:
Before I mix paint I open a tack rag completely and lay it somewhere clean to allow it to air out. You can now mix your paint with gloves on. I also start wearing my breathing mask at this point. At the very least I wear a respirator. Tack off the everything. I sprayed the primer on the portions I did body work to and on each coat extended the paint past the previous coat. I used 3 medium wet coats.
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar012.jpg">
Blocking Primer:
Spraying a guide coat helps you to be sure your panels are straight. You can spray the guide coat while the primer is still wet to allow it to sink in if you want. The longer the board the straighter the panel still stands. You want to sand until you have no more guide coat.
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar014.jpg">
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar006.jpg">
Prep for Sealer:
Wetting the floor helps to keep the dust down. Once again you clean the surface. You must tape everything you dont want paint on and anywhere you dont want paint. Think paint will get everywhere on the car there isn't paint so if in doubt tape it. Also if you want a soft edge fold the tape over on its self. The paint will do this its self if you pull it while masking. Do not use cheap masking tape. I used a post sanding wash and then diluted alcohol over that. Once again open a tack rag. You can now mix the paint. I spray everything with sealer. It allows me to see any flaws and also keeps anything from bleeding through. The sealer I used only requires one wet coat.
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar020.jpg">
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar019.jpg">
Basecoat:
I use a wet on wet sealer. Open a tack rag and mix the paint. Tack off everything. I then sprayed 3 medium coats. Always wait the required time between coats and between clear.
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar028.jpg">
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar027.jpg">
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/richscar025.jpg">
Clear:
For clear I sprayed 3 coats on the car. If you plan to wet sand you will want to spray more. I was unable to use my breathing machine and the clear began to bother me. Clear is the most dangerous to spray because of the chemicals it contains. The most dangerous chemical is odorless. You want to lay down nice wet coats of clear. If the first coat of clear is orange peeled then all the rest will also be. At this point I was still learning and sprayed too fast giving me orange peal. This helps the write-up but not me lol. You can also spray ~3 coats of clear, wet sand, and then respray more clear coat. The added clear coat is called flow coats.
<img src="http://img.photobucket.com/albums/v110/hampp2/8b4dfb12.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/b05f2e35.jpg">
Wetsanding:
Wet sanding should not be needed on this type of paint job. However due to my lack of experience I shot the clear and orange peeled it. It is said the perfect spray is right between orange peel and runs. I let the clear begin to cure before sanding. This makes the clear harder. You do not want to sand any edges when you sand. You will sand right through very fast. I mask off the edges of the panel and any sharp edges to allow me to work faster. I usually start with 1500 but if there is a lot of orange peel then I will step down to 1000. I also like to end with 2000 before buffing.
<img src="http://img.photobucket.com/albums/v110/hampp2/22532e41.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/2f6515fe.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/ce8e9677.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/3fa16359.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/e702615a.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/f53cb3b5.jpg">
Buffing:
Remove the tape. I used a circular dewalt buffer. It has speeds between 1000 and 3000 rpm. A sander/grinder which looks just like it will have speeds starting at 3000rpm. This is too fast for what you want. I start out either using a wool pad or a yellow one. You begin to work up from there. You never want to stay in the same place with any buffer especially a buffer like this. You then can work your way up through pads and compounds. I am still experimenting with different compounds and pads so you will have to find out on your own.
<img src="http://img166.imageshack.us/img166/877/rich3ir9.jpg">
<img src="http://img166.imageshack.us/img166/877/rich3ir9.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/d35c427c.jpg">
<img src="http://img.photobucket.com/albums/v110/hampp2/1c478c24.jpg">
<img src="http://i70.photobucket.com/albums/i116/mnieroda28/IMG_3766.jpg">
Your car should be done now. Wait at least 4-6 weeks before wax.
Tools and Equipment Used:
Air compressor, DA Sander, Rubbing Alcohol, Pre and Post Sanding Prep Spray/Wash, Dish Washing Soap, 40 Grit Sandpaper, 60 Grit Sandpaper, 320 Grit Sandpaper, 400 Grit Sandpaper, 1000 Grit Sand Paper, 1500 Grit Sand Paper, 2000 Sand Paper, Nylon Pad, Paint Gun with Proper Fluid Tip, Air Respirator, Air Machine, Mixing Cups, Filters, Gun Filter, Stir Sticks, 3m Cup and Bag, Rage Extreme Filler, Metal Glaze, Guide Coat, Board Sanders Various Sizes, Hard Sanding Blocks, Flexible Sanding Blocks, Welder, Hammer and Dolly, Various Hand Tools, Circular Buffer, Buffing Pads, Buffing Compounds and Polishes, Welding Mask

General Tips:
Never mix into your paint gun cup. Always mix and then filter the paint into your gun. This is true for anything you want to spray.

Your paint manufacture will have tech sheets on how to mix the paint and times to wait. Do not deviate from these.

Also it is best to use the same paint manufacture throughout.

Paint will not stick to shiny spots.

Wear gloves whenever possible to avoid touching bare metal or final sanded paint.

Always stop to fix mistakes. They will not fix themselves as you go further along in the paint process.

Do not use cheap masking tape.


Now your done. Step back and admire your work. It's been earned.

Also look at my how to paint a bumper post if you are interested in painting plastic parts.

djordan

Move the on/off switch back and forth several (usually takes about 20 for me) times and push the set/decel switch several times. This will scrape some of the oxidation off of the switch contacts to keep the switch working for a little while.
I've been doing this every week or so because I've been too lazy to properly clean the switch.

Living Dissed

The above switch cleaning advice is not thorough enough. In fact, if you follow this advice, and mearly remove the covers, your solvent will probably turn the detent grease and accumulated hand sweat into shellac, and cause more problems than it solves.

To really clean the switch, you have to remove it from the stalk. First, follow the other directions up to the point where you remove the covers.

To remove the switch from the stalk, you need to get some slack in the wires. You'll have to remove the two small philips-head screws holding the six-pin connector to the back of the stalk cluster. Remove the two screws, unwrap the wires from the stalk, and you'll be able to push the wires into the stalk.

After you've removed the covers from the switch, it should be obvious how to release the switch from the stalk. On the back, at the end, is a small piece of plastic, and a sloping piece which locks as the switch is inserted. Use a very small screw driver, or some other small probe, to lift the plastic, and the stalk switch slides out.

Once you have the switch out, it can be disassembled. The Set switch is held in by tabs on top and bottom. You should make note of the relationship between the parts, though, in the end, there's only one way to reassemble them.

Once the Set switch is out of the way, you can go to the inner end of the switch, where there's a small tab holding the circuit board in. Press this tab, and the circuit board and white set of switch contacts comes out the same end as the Set switch. The switch truck has two sets on contacts on one side, and one on the other, so you should make note of the relationship of the switch contacts. However, the wear patterns on the circuit board should tell you how it is oriented.

Mine was really filthy. It took a couple of passes with q-tips and electronic cleaner to get it all up.

Reassembly is the reverse of disassembly. I was sent an inquiry about the orientation of the roller. The roller is designed to lift over the bump when the cruise control is turned on. Sitting in the driver's seat, the roller is oriented so it's central axis goes around the circumference of the circle described by the stalk's motion. The factory used a little brown grease on the roller, so once everthing was clean, I applied just a little.

Living Dissed

Additional Cruise Control Diagnostics.

a-aranda set the bar with his excellent Cruise Control diagnostic. I'm happy to provide this addition. I appreciate all improvements anyone can offer to my input, and hope the audiworld moderators will help us all produce an excellent document. First, I'd like to clarify a couple of items in a-aranda's FAQ:

A. "Control Unit: This piece rarely goes bad...." My malfunction turned out to be the Control Unit, and my dismantler says they sell quite a few of them.
B. a-aranda says "the bellows should move the throttle a bit (nowhere near WOT)." I don't know what a "Mity-vac" is, but my vacuum bellows test using the Audi components sucked the diaphram in all the way.
C. "Part number for the control unit is 4B0 907 305." Audi uses the same Control Unit for 4, 6, and 8 models up until 2002, with the earlier cars having part number 4D0 907 305. Part 4B0 907 305 is listed as superceding 4D0 907 305. The pinout is the same, and probably the only difference is in the generation of electronics inside the module.
D. a-aranda's test of the control unit came up with some values corresponding to testing with the controller connected, and some with it disconnected.
E. While he seemed to detest working on the Control Unit, feeling it could only be done upside down in the passenger footwell, I was able to dangle the pack, push back the passenger seat, and work bent at the waist. Your mileage may vary.

The Control Unit uses a combination of passive and active circuits. The circuits are designed, ingeneously, to fail safe, and fail to ground.

Explanation of the Control Unit pinout, followed by detailed diagnostics:

1. Ground - not present in all models
2. Not used
3. Not used
4. Signal from the Set/Decelerate button. With the system powered, pressing the Set/Decel button should cause pin 4 to have a +12 volt event.
5. Ground
6. Return from Vacuum Pump. When accelerating, this wire should have 0 resistance to ground. Otherwise, it should have resistance to ground. The Control Unit works with dual redundancy by supplying +12 volts on pin 7, and connecting pin 6 to ground to accelerate. If either the +12 quits, or there is no longer a connection to ground, the Cruise Control deactivates.
7. Power to Vacuum Pump and Vacuum Hold Valve. When activated, this pin should have +12 volts. Instead of testing the vacuum system piece-by-piece, I connected pin 7 of the Cruise Unit's connector to +12, and connected pins 6 and 12 to ground. The vacuum pump sucked the bellows in all the way. Additionally, I was able to see the brake valve dump vacuum, and - I have an automatic - assume a working clutch vacuum dump valve would do the same.
8. Power supply, from pin 4 of the Stalk Switch. On the Stalk Switch, the connection between pins 4 and 5 is the Control Unit's On/Off. On a manual transmission car, pin 5 of the Stalk Switch is powered by fuse 31. On automatic transmission cars, pin 5 of the Stalk Switch is powered by pin 9 of the Transmission Control Module, modulated to ground by pin 5 of the Multi-Function Transmission Range (TR) Switch. In short, on an automatic, the Cruise Control Unit is only powered when the car is in a Drive gear.
9. Vehicle speed input from pin 6 of the yellow 26-pin Instrument Cluster connector. Probably a square wave, with a low of 0 volts and a high of +12 volts, ranging from 10% to 90%, depending on vehicle speed.
10. Resume/Accelerate momentary switch. When the Stalk Switch Res/Accel is pressed, this pin should shift from 0 volts to +12 volts.
11. Brake light circuit. As opposed to all the other passive circuits, this circuit is active, sending +12 volts to ground through a normally-closed brake switch, and then through the cold brake light filaments. When the brake is pressed, this circuit from pin 11 detects the connection to ground is broken, and the Control Unit disengages. Having both brake lights out can also cause the system to malfunction (check 'em!). The Momentary Off switch on the Stalk Switch is in series with the brake switch; the Control Unit detects pressing the Stalk Switch Momentary Off as the same event as pressing the brakes.
12. Return from Vacuum Hold Valve. When tracking a speed, the Control Unit activates the Vacuum Hold Valve to maintain the vacuum. In the event of power failure, the Hold Valve releases. Like the Vacuum Pump, the Control Unit manages the Vacuum Hold Valve by controlling the routing of the return wire to ground. when activated, there is no resistance to ground. When dumped, there is resistance to ground.


A detailed breakdown of values at the Cruise Control Connector. The first five are with the Control Unit removed from the harness:

Controller removed, power off; resistance-to-ground values:
1. 0.
4. Infinity, going to 0 when the Set/Decel switch is pressed; if less, dirty stalk switch.
5. 0; if less, dirty stalk switch.
6. Infinity.
7. Infinity.
8. Infinity when Stalk Switch is off, 1 ohm when Stalk Switch is on, as voltage bleeds across the brake lights.
9. 3 ohms resistance as the ohmmeter charges an output-filter capacitor on the instrument panel, followed by a brief period of 0 ohms as the capacitor outputs, cycle repeating.
10. Infinity when Stalk Switch is off; when the Stalk Switch is on and the Res/Accel button is pushed, 1 ohm through a backtrack to the brake lights.
11. Infinity when Stalk Switch is off; when the Stalk Switch is on and either the Momentary Off or the brake is pressed, 0 ohm. If less than 0, dirty Stalk Switch.
12. Infinity.

The next four are with the Control Unit removed, but with the system powered (Manual: key turned to ignition; Auto: key to ignition, transmission in drive):
Controller removed, system powered, Stalk Switch OFF, voltage:
1. 0.
4. 0.
5. 0.
6. 0.
7. 0.
8. 0.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 0.
11. 0.
12. 0.

Controller removed, system powered, Stalk Switch ON, voltage:
1. 0.
4. 0; when Set/Decel is pressed, +12 volts.
5. 0.
6. 0.
7. 0.
8. 0.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 0; when Res/Accel is pressed, +12 volts.
11. 0.
12. 0.

Controller removed, system powered, Stalk Switch OFF, resistance to ground:
1. 0.
4. Infinity.
5. 0.
6. Infinity.
7. Infinity.
8. Infinity.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. Infinity.
11. Infinity.
12. Infinity.

Controller removed, system powered, Stalk Switch ON, resistance to ground:
1. 0.
4. Infinity, going to 0 when Set/Decel is pushed.
5. 0.
6. Infinity.
7. Infinity.
8. 0.
9. 3 ohms resistance as the ohmmeter charges an output-filter capacitor on the instrument panel, followed by a brief period of 0 ohms as the capacitor outputs, cycle repeating.
10. Infinity, going to 0 when Res/Accel is pushed.
11. 0.
12. Infinity.


The next five are with the Control Unit installed in the harness:

Controller installed, power off; resistance-to-ground values:
1. 0.
4. 1 ohm.
5. 0.
6. 1 ohm.
7. 1 ohm.
8. Infinity when the Stalk Switch is off. When the Stalk Switch is on, 1 ohm bleeding through the brake lights. While Stalk Switch is on:
- Set/Decel should change the resistance to .5 ohm.
- Res/Accel should change it to .5 ohm.
- Momentary Off should change it to 1.5 ohm.
9. 3 ohms resistance as the ohmmeter charges an output-filter capacitor on the instrument panel, followed by a brief period of 0 ohms as the capacitor outputs, cycle repeating.
10. 1 ohm, going to .5 ohm when Res/Accel is pressed.
11. Infinity when the Stalk Switch is off. When the Stalk Switch is on, 0 ohms resistance, changing to 3 ohm when either the momentary off or the brake is pressed.
12. 1 ohm.

The next four are with the Control Unit installed, and the system powered (Manual: key turned to ignition; Auto: key to ignition, transmission in drive):

Controller installed, system powered, Stalk Switch OFF, voltage:
1. 0.
4. 0.
5. 0.
6. 0.
7. 0.
8. 0.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 0.
11. 0.
12. 0.

Controller installed, system powered, Stalk Switch ON, voltage:
1. 0.
4. 0; when Set/Decel is pushed, +12 volts
5. 0.
6. 0.
7. 0.
8. +12 volts.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 0; when Res/Accel is pushed, +12 volts.
11. Appears to be 0, but is actually a +12 volt, low amperage, active sensor signal sent to detect continuity to ground through the cold brake lights. Because this signal is soaked up by the gound, pressing the Momentary Off or the brakes will make it appear voltage is being passed to pin 11, but what is really happening is the ground is being removed, and the meter goes from not detecting, to becoming the best path to ground and detecting +12 volts.
12. 0.

Controller installed, system powered, Stalk Switch OFF, resistance to ground:
1. 0.
4. 1 ohm
5. 0.
6. 1 ohm.
7. 1 ohm.
8. Infinity; pressing Set/Decel should show 1 ohm on the backtrack through the brakelights.
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 1 ohm.
11. Infinity.
12. 1 ohm.

Controller installed, system powered, Stalk Switch ON, resistance to ground:
1. 0.
4. 1 ohm; Don't press Set/Decel! +12 volts! It might fry your meter input!
5. 0.
6. 1 ohm.
7. 1 ohm.
8. Don't touch a resistance probe to pin 8 with the Control Unit powered! +12 volts! It might fry your meter input!
9. Depending on your meter, appears to be 0, but is actually a few millivolts positive power from the instrument panel.
10. 1 ohm. Don't press Res/Accel! +12 volts! It might fry your meter input!
11. 0, Don't press Momentary Off or brakes! +12 volts! It might fry your meter input!
12. 1 ohm.


Stalk Switch, as events:

Turning the unit on:
Stalk Switch pins 4 and 5 become connected. When off, no voltage should be detected at the Control Unit. When on, and the ignition on, and automatic cars in Drive, +12 volts should appear at pin 8 of the Control Unit.

Pressing the Set/Decel button:
Stalk Switch pins 3 and 4 become connected. At the Control Unit, pin 4 becomes powered.

Pressing the Res/Accel button:
Stalk Switch pins 2 and 4 become connected. At the Control Unit, pin 10 becomes powered.

Pressing the Momentary off:
Stalk Switch pins 1 and 6 become disconnected. The Momentary Off switch on the Stalk Switch is in series with the brake switch; the Control Unit detects pressing the Stalk Switch Momentary Off as the same event as pressing the brakes. At the Control Unit, pin 11 should detect the events.


Tidbits:

Testing the vacuum system:
The vacuum pump itself is under the ABS controller, and hard to get to. You can test the entire vacuum system from the controller.
First, you'll have to have the engine cover off, so you can see the CC throttle bellows. Connect pin 7 of the Cruise Unit's connector to +12, and connected pins 6 and 12 to ground. Walk around to the engine bay, and if the vacuum pump has sucked the bellows in all the way, you've proven the system has sufficient suction. If you have someone with you, have them press the brake pedal while you watch the bellows. When they press the pedal, the bellows should open. When they release the pedal, the bellows should close back down.
This test is now over, and you can either disregard the vacuum system, or know where to fix it.

Testing the electrical system:
In time, the stalk switch connections get tarnished. You can probably count on needing to take it apart and clean it every five years or so.
If you've cleaned it, and the module still won't engage, you can test the wiring and switches from the connector of the cruise control module.
If you get weak events, where you press a switch and get 9 volts, or instead of continuity you get a few ohms of resistance, then the stalk switch has dirty contacts.
If you get solid events, where you press a stalk switch and the voltage swings from 0 to 12, or the resistance swings from 0 to continuity, then the switch is fine - most likely, the relay in the controller has failed. The fix is replacement.


In the Bentley manual, the circuit diagram for the Cruise Control on a car equipped with automatic transmission lists a connector, T4b, as being black, and at the center console rear. I was unable to find this connector in the manual transmission diagrams. The four wires are:
1. Power, +12 volts from fuse 5
2. Vehicle speed from pin 6 of the yellow 26-pin instrument connector
3. Ground
4. Drive indication from pin 9 of the Transmission Controller, modulated to ground by pin 5 of the Transmission Range Switch, through the on/off of the Stalk Switch. This signal is the same as pin 8 of the Control Unit, and is only powered when the car is in drive, and the Cruise Control is On (not necessarily engaged).

This connector seems to be positioned for an optional rear differential lockup. However, on my car (a '96), it is not in the rear of the Center Console, but in the right end panel of the dashboard, beneath the end cover. This placement makes its usefulness for a rear differential questionable, however, it might be very useful if you need to know whether your Control Unit is being powered on pin 8, need a convenient ground or +12 volts for testing, or want to hook up an oscilliscope to read the speedometer square wave.

Sal R.

A gray relay marked #373 located under the driver's side knee bolster just under the steering column.<ul><li><a href="https://forums.audiworld.com/a4/msgs/2594245.phtml">https://forums.audiworld.com/a4/msgs/2594245.phtml</a</li></ul>

Sal R.

Possible reasons:
You have a leak.
Damaged or failed pressure switch on condensor.
Gummed up/destoryed lowside orifice/filter.
<a href="https://forums.audiworld.com/a4/msgs/2365838.phtml">Compressor issues</a>
Compressor is dead.
Need a <a href="https://www.audiworld.com/tech/misc34.shtml">recharge</a> of R-134a

Running an output test on the climate control system using VAG-COM can help you figure out where there is a failure in the system.

GL and keep cool.

Nkugs90

<ul><li><a href="http://www.fap99.com">http://www.fap99.com</a</li></ul>