Instrument cluster dead in the cold

I've got a problem with the gf's 2001 Audi A3. The instrument cluster is completely dead first thing in the morning when the car is cold, but after about 20 minutes of driving the whole thing pops into life. The car starts up fine, its just that you're driving with a completely inert display.. no speedo, fuel gauges, temp, clock etc..

I've taken out the cluster and checked that the connectors going into it aren't loose and I've also replaced all the fuses relating to the instrument panel but its still there. Today I called up Audi and they said it sounds like it needs a new instrument cluster which will cost serious £££.

Any other hints?

Reply to
Don Turner
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sell it/px it while its warm

Reply to
Angus McCoatup

Is it only when the weather's cold or when the car's cold? It sounds to me like a bad connection that gets made when the area heats up. Possibly a cracked track or dry solder joint on the circuit board. I doubt it needs a new panel but possibly a bit diagnosis with a multimeter and then a simple fix.

Try putting it in the fridge or freezer for a few hours then check connectivity on the PCB tracks. Multimeters are pretty cheap from Maplins or similar. Soldering is easy but there's a knack so if you're not confident, get someone who is.

Alternatively you could try sourcing a 2nd hand cluster from a similar car to test if it's the cluster or not.

Reply to
Dave

Hi Dave,

It only happens when the weather is cold. For example when I park over-night in a garage which is heated the cluster works first time. Also if I start the car for the first time when its been sitting in the sun (mid afternoon) it is also fine.

You may be right with respect to it being a bad solder joint or track however I would do more damage than good if I attempted to find it. I opened up the cluster earlier and there are dozens of surface mounted chips with tiny solder joints.

Does anyone know of a good circuit board electrician in London or the home counties??

Cheers Don

Reply to
Don Turner

Just get a new one from a scrapper.

Andy

Reply to
akd

I've looked into this and assuming I could find the exact same model I would need to get the mileage corrected to the current mileage (around £120) and then I would need to take the car down to Audi for them to reprogram the replacement since the engine immobiliser is integrated into the instrument cluster.

So I would much rather try and salvage what I've got first.

Cheers Don

Reply to
Don Turner

Could the problem be in the grounding of the cluster to the body and / or grounding of the body to the engine? Check gounds in the engine compartment where there are wide temperature swings.

Reply to
Tony

It's much more likely to be a bad solder joint or a fractured pcb track, it's vibration that kills them. If you can use the car with the pcb accessible, then gently flex the board in various directions to see if you can make the fault come and go. By flexing smaller portions of the board you may be able to identify an approximate area to investigate with a magnifying glass. Another method is to get some electronic freezer spray (that water pipe freezer stuff is OK though) and a hair drier to temperature cycle areas of the pcb. You still need to resolder though.

A bodge may be to permanently flex the board with something jammed against it in the appropriate direction. Then it's fingers crossed.

Reply to
SteveB

Given how crucial the instruments are to safe and legal driving, having them fail after 4 years or so is hardly "fit for purpose". How hard have you tried beating on the dealer to get Audi to contribute some or all of the cost of replacement ?

Reply to
John Laird

Take the cluster out while it's cold, leaving it connected, and try connecting across soldered joints with a piece of wire to see if suddenly springs to life. At least you'd then know which bit is faulty and then decided how best to repair it.

Rob Graham

Reply to
Rob graham

Hi Don

Pop into Maplins with a tenner in your hand, buy a can of freezer spray, go into McDonald's drive through and get a big Mac with the change, Go home.

Open up your dash whilst its warm and working, pick a corner of the display system and give it a short squirt with the freezer, if the display vanishes you're in the right area, continue this until you can localise to one component or PCB area and diagnose accordingly.

Reply to
Steve Sweet

AS it is dead when it fails, it's more likely to be something like a voltage regulator with a dodgy connection. These are among the larger compnenents, so they are easy to hand-solder, and of course they tend to heat up and cool down in use. I'd start by looking for that.

If you know anyone who has TV repair experience they could be worth a try- the majority of intermittent TV faults are soldering too.

Reply to
Chris Bartram

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