audi a4 temperture gauge

[wing0706]

hi i have a 1998 audi a4 anvent 1.9 tdi am having probs with temp gauge and red lights in door when the red lights on door panel dont work neither do the temp gauge
didnt know if someone has had this prob sometimes they work sometimes they dont have change the temp sensor but the gauge still will not work any ideas please
thanks mark :aargh4::aargh4:

[Whippy53]

Hi Mark, sorry, can't help I'm afraid. You might try a scan though. See what that throws up.

[fat controller]

I have no knowledge of the car or the fault, but my head is screaming 'earth fault' simply because the puddle lights seem to be related? I'd be inclined to check the wiring loom in both doors (predominantly drivers side though), and back to the fuse box paying special attention to any body earths that there are.

I have a feeling that this might be one of those faults that needs an old fashioned approach of methodically working through, cleaning and remaking connections.

[wing0706]

ok thanks

[Szaxx]

For a quick check on the earth fault, connect a wire from the doors body metalwork to the car body metalwork, make sure its clean metal, no rust or paint etc.
A quick lead is a starter cable, its big but will work.

[wing0706]

Thanks done what you said ran earth from body work to puddle lights still no joy sometimes they work sometimes not must be deeper prob in motor somewhere temp gauge i sorted the new sensor i put in was faulty so got another one and now it ok just need to sort puddle lights

[Szaxx]

A second check on the.lights.
You'll need a volt meter or a small 12 volt bulb ideally smaller than the lights being checked.
Undo the clips screws etc to expose the bulb. I'll assume its a.standard unit for now.
Find a good ground point on the cars bodywork, not the doors and put the negative lead on this if using a meter. Put the pos lead ( usually red) on each side of the light if exposed or remove the bulb carefully and locate the connection points. Be careful not to touch more than one at a time. A short could take a fuse out or possibly damage the electronics.
A piece of tape or tubing over the test lead leaving the tip exposed is a good way to prevent this.
With the door open you should get 12 volts or slightly more from one lamp terminal and 0 volts from the other. This requires a clean and new bulb.
If you get 12 volts at both terminals the return neg lead is broken. It could also be normal if you have a pin switch fitted to operate the bulbs, these are rarely used after the 80's. It looks like a 5mm or so button that gets pushed in when the door closes. Located between the hinges normally.
If you get no volts at either bulb connection then the operating switch or the cables are open circuit. This is a panel off job and a wiggle on the cables to locate the break.
If this reveals nothing then the switch unit is inside the cars bodywork. It could be one of a few types and a schematic of the cars electrics will be required to see what controls the lights.
Theres a possibility the alarm uses this same circuit as a trigger so don't be tempted to put 12 volts onto the lamp. Thats a bad move.
If you only have a small indicator light use this in place of the meter. It may glow less bright if the return ground is broken.
Hope this helps you to analyse the fault.

[wing0706]

hi thanks try all of the above and got no power to any of the door lights they only seem to work when they want to will have to strip door panel down and find switch as when i open any of the 4 doors they only work when they feel like it these probs fry your brain lol thanks for all your help

[Garnet19]

just sold my old A4 1.9 Tdi Avant had it for 15 years. never had any trouble with temp gauge, sorry cant help with that one.

[wing0706]

got temp gauge sorted i was sold a faulty sender got another one and all good thanks just trying to sort out puddle lights now
thanks

[Szaxx]

If NONE of them work, change the fuse. I don't have a wiring diagram handy but it sounds like the supply to all of them is defective not the door switch as theres more than one out of action.
I misunderstood the fault thinking its only one door.

[wing0706]

cant find fuse emmm was thinking it might be the micro switc stuck shut so its thinking the doors are shut even when open i been looking for fuse but cant find a dia which tells you which one it is must be on a curcit with something else but thanks alot for all your help

[wing0706]

Right just to let you know puddle lights sorted it was a sticky relay £37 from audi so went to scrap yard and got one all done at last thanks for your help

[Szaxx]

You're welcome.
I only found a basic diagram and it showed very little. If your interior lights work ok then the fuse is ok too.
Glad its sorted.