Temperature Gauge not reading

[peso]

My temperature gauge stopped reading a few weeks back? Has this happened to anyone and any ideas of what the fix is? Thank you for any help in advance.

[silverd2]

Originally Posted by peso

My temperature gauge stopped reading a few weeks back? Has this happened to anyone and any ideas of what the fix is? Thank you for any help in advance.

I assume you have prefacelift A8(?)...most FL owners state the year of their car.
If so, the sensor for your coolant temp gauge (G82) is on the front of your engine. Gauges rarely fail, but sensors commonly do.

Check the wiring and good, tight connection...if it looks good, could be a failed sensor.

[peso]

thanks, will check tomorrow. its a '98 prefacelift obviously

[A8CT]

Yes, it's the coolant temp sensor. Back of the engine, green top. It's abt a $20 part.

Bob

[silverd2]

Originally Posted by A8CT

Yes, it's the coolant temp sensor. Back of the engine, green top. It's abt a $20 part.

Bob

Just going by the Gospel according to Saint Bentley of Cambridge, but, don't 32V engines (don't ahve one to look at) have 2 sensors? ...one on the back (G62)for ECM signal and the one on front (G82) (drawing) for gauge reading?

[Prospeeder]

The 4 pin for the ECU also does the gauge. The Other sensor is actually the fan switch

[silverd2]

Originally Posted by Prospeeder

The 4 pin for the ECU also does the gauge. The Other sensor is actually the fan switch

Yes and no and no >>>

ONLY 40V D2's (00-03) have the 4 pin sensor containing 2 separate sensors (one to the ECM and for the gauge) attached on top of coolant pipe behind engine.

32V D2's (97-99) have 2 coolant temp senders, both 2 pins each...one on the rear of of bank #1 cylinder head and the second on front of block (drawing, parts catalogs, service manual, real life, etc)...one for gauge & one for ECM (wiring diagrams).
Neither of these has anything to do with electric radiator (condenser) fan.

All D2's (as with most VW's & Audi's) have a thermal switch at bottom right of radiator that turns on the electric fan...that and the the climate control (or AC high pressure switch, when called for).

[Prospeeder]

According to shop manuals. There are actually 3. One for ECU the G62 on the back of the bank 1 cylinder head. Another for the gauge G82 on the cylinder block below the upper radiator hose. And the 2 in one F18/F54 sensor as the thermo cooling fan switch. Later models had 2. The 4 pin two in one for gauge and ecu. and a seperate 4 pin fan switch. I can pull out genuine audi manual pictures if you really dont think so.

[silverd2]

Originally Posted by Prospeeder

According to shop manuals. There are actually 3. One for ECU the G62 on the back of the bank 1 cylinder head. Another for the gauge G82 on the cylinder block below the upper radiator hose. And the 2 in one F18/F54 sensor as the thermo cooling fan switch. Later models had 2. The 4 pin two in one for gauge and ecu. and a seperate 4 pin fan switch. I can pull out genuine audi manual pictures if you really dont think so.

Good Lord..you don't like admitting you're wrong any more than I do...and especially don't seem to like admitting anyone else is right, huh?

You just repeated everything I stated about temp "SENSORS"...TWO of them on PFL and ONE on FL...AND contradicted yourself at the same time: you plainly stated before (about the sensor on the front, G82) "The Other sensor is actually the fan switch"

The fan SWITCH(es) on either car is NOT called a sensor by Audi, for good reason...technically it isn't...it's 2 (in one unit) on/off "SWITCHES" triggered by high, then higher temperatures.
G62 and G82 (G2 on FL combines with G62) are sensors/senders emitting specific measured signals according to specific varied temps.
Yes the thermal switch has to "sense" temperature to trip a "switch", but I'm using Audi's own terminology (example: "oil pressure SWITCH"...not sensor)...just like the ignition switch has to "sense" that you're twisting it to start your car...so it's a "key sensor", instead of a "switch", huh?

Bentley IS an "Audi shop manual", containing ONLY info (including drawings) supplied directly (and unchanged) from AUDI.

Why would I need photos? ...esp when all you did was repeat my words (take a minute to actually READ my last post). I've actually had these exact sensors and switches out in my own hand, checked em out with a meter, replaced G2/62 on my D2 (and other sensors & switches my past VW's & Porsche's)..."real life".
Don't you have a D2 in your driveway to look at these in person?

I humbly accept your admission of defeat

[A8CT]

I gave you a facelift answer for what that's worth