Herve

I want to replace the gauge faces (c'mon, everybody does it !) but to replace the surface-mounted tiny red LEDs with blue ones. This "blue digits with red needles" look would be very close to the 2001 instruments.

On my 1999 A6, the instrument cluster is manufactured by VDO. I have searched the forums and found that some needles can be removed (they pop-out), some cannot, depending on... well nobody knows, including VDO themselves.
Has anyone done it on a 1999 A6 (I assume cluster would be the same throughout the whole year).
Thanks

Herve

I meant : I DON'T want to replace the faces BUT only the LEDs.

stumbo

Don't ask why, if I tell you, I'd have to kill you

But with BMW/VW/Audi the VDO instrument clusters are essetialy the same. Rear plastic moulding containing the main circuit board (connectors directly mounted - so take care). Individual coils (and digital displays) pluged into circuit board through plastic moulding. Coils forward mounted onto clear prisms. Graphics glued to front of prisms. Nedles pushed onto coil spindles and hammered home with a single short knock. front binacle surrounds all and sits flush with graphics.

The needles can be a bugger to get off. The 'knock' is ment to be applied as with a torque rench but has the effect of very securely attatching it to the spindle.

If you get a ply tool, summit with 2 short prongs to sit either side of the spindle, base rest on the graphic (rem protection) and lever off the neddle, you could pull the spindle out the coil. Then your screwed, there a rela pane to get back in & calibrate correctly.

We used to apply a tool on the back of the prism, sitting around the spindle. The spindle should have a little brass/summit gromit type thing on it. If this is prevented from going any further forward when you try to ply off the needle, you should protect the coil. For this second tool, took a scalple blade, broke in two across the slot. Then wrap the blade end in tape. hold the tape end, and push the *now* open slot onto the spindle between the coil and the prism. It was just the correct size to stop the gromit/spindle bit from being pulled forward when you plyed off the needle.

We had about a 80% success rate. But this took alot of time, and we had limitless supply of replacement parts. All in all, I would recomend against it, unless you have a model makers hands and nerve and can afford to get the profesionals to sort it if it all goes wrong.

P.S. which gauges are hard and which are easy, depends on the gauge spindle width, the mchine tolerance knocking the needle on at the time, and any thread-lock type stuff that was in production at the time.

stumbo

LEDS? Are you talking warning lights ? These are just light tunnels through the various mouldings, bulbs plug in back (into circuit board) and at front of tunnel is the graphic.

I've got the feeling that your talking about summit else, having never sat in an A6 I not sure whats in the instrument cluster. I wait for a response

Herve

Thanks for your detailed answer.
I only saw what I *think* are surface-mounted LEDs. Maybe they are not, and the red background light is coming from a set of bulbs in the back, as you suggest ?
I will check by plugging the cluster without its plastic trims, to see where the red glow is coming from.
Having said that, your post scared me enough to reconsider this project (the idea of breaking a coil, and NO I don't have unlimited spare parts !! :-)

stumbo

With the huge extra life of LEDs, they *may* now be surface mounted.

As in just behind the prism/graphic, shrouded in some kind of cap to prevent light bleed. It would save a fortune on main moulding costs. But it would need a transparent FPC (flexible circuit board) to keep it economic in production.

{cough....cough} please excuse me, got carried away, you would never guess my cars in the body shop, and I'm twiddleing my thumbs . But I get it back today .......

Ref: scared you

Sorry about that, I'm sure others would disagree with my pesimism/nervousness. I just wanted to let you know that I *think* you still need to ply the needle from the front, whilst alerting you to the very real potential danger to the coil.

If you only want to replace the LEDs (and you find they are indeed LEDs) you may not need to remove the needle. Remebering I've only worked on BMW/VW packs (but they are all VDO, and one basic design), Each individual gauge should be removable intack [coil + prism + graphic + needle], how LEDs fit into this I'm not sure. I used to retro fit them, but thats not the point, I'm sure VDO do it *properly*

stumbo

>Herve > any progress ?