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View Full Version : Repairing intermittent water temp and fuel gauges (80/90/100)



arcane
December 22nd, 2005, 04:12 PM
Overview: This how-to is the first of (hopefully) many to come, providing instructions on how to repair common problems with the Audi 80. Some of these guides may be applicable to other models (90 / 100), although as the author does not have access to either of these, it cannot be assured. This particular how-to addresses the intermittent water temperature and fuel level gauges – a fault which arises after approximately 10 years.

http://img525.imageshack.us/img525/1092/dash14yi.jpg (http://imageshack.us)

Time to complete: Around 20 minutes (look at the clock in the photos!)

Tools required: A long Philips-head screwdriver, some fine sand paper (400 grit)

Instructions:
The first step is to remove the top-half of the steering column surround. To do this, remove the two screws found on the underside of the steering column surround, as shown in the picture below:

http://img525.imageshack.us/img525/2595/dash28uw.jpg (http://imageshack.us)

Following this, you should be able to raise the upper-half of the steering column surround (as shown in the picture below). To completely remove this piece, the rear end (i.e. the end closest to the dash cluster) should be lifted first, tilting the piece. This will allow it to clear the various controls protruding from the dash cluster. After tilting it slightly, it should be able to be pulled upwards until it’s completely free.

http://img525.imageshack.us/img525/2228/dash34hh.jpg (http://imageshack.us)

With the upper-half of the steering column surround removed, the next step is to remove a connector which sits in the way (indicated below). The easiest way to do this is to first remove the actual connector itself, by lifting the end closest to the steering-wheel up – it should unclip from the bracket. After this, pull the metal bracket towards the steering-wheel and it should come free.

http://img525.imageshack.us/img525/3354/dash42uy.jpg (http://imageshack.us)

Once the connector is out of the way, the two screws holding the dash cluster in (pictured below) can be undone.

http://img525.imageshack.us/img525/2330/dash54ku.jpg (http://imageshack.us)

Follow this, hold onto the rubber piece with the text “UN4” and pull towards the steering-wheel, pulling slightly upwards. The dash cluster should slowly come out.

http://img525.imageshack.us/img525/1382/dash65ew.jpg (http://imageshack.us)

Keep pulling until the rear of the dash cluster is free from the dash cluster surround:

http://img525.imageshack.us/img525/637/dash78jo.jpg (http://imageshack.us)

At this stage, the bottom of the dash cluster can be tilted upwards, and the entire cluster can rest on the steering-column:

http://img525.imageshack.us/img525/6999/dash80se.jpg (http://imageshack.us)

The connections to the water temperature and fuel level gauges are now accessible. Essentially, each gauge uses two screws for the connection, as opposed to soldered joints. The interface between the circuit board of the dash, and the washer on the screw, becomes oxidized after many years, and a bad connection results. What we want to do is unscrew each screw, one at a time, and using the fine sand paper, carefully sand the contact-points for each screw. Care must be taken to ensure only one screw is ever out at any one time, otherwise the gauge itself may become misaligned. The screws we need to work with are indicated below:

http://img326.imageshack.us/img326/568/dash94rk.jpg (http://imageshack.us)

http://img326.imageshack.us/img326/595/dash104da.jpg (http://imageshack.us)

As they say, installation is the reverse of removal. When putting the dash cluster back into the dash surround, the upper-half needs to be tilted backwards (i.e. towards the front of the car) slightly, otherwise it will not go in. The fit is quite snug, so a little bit of force is required to push it back into position.

Remember to replace the metal bracket, and the connector which was removed earlier on. When replacing the upper-half of the steering column surround, it’s usually easier to put the front-end (i.e. the half closest to the steering-wheel) in first, then lower the rear half. If all goes well, the gauges should now work all the time!

http://img525.imageshack.us/img525/7900/dash111lq.jpg (http://imageshack.us)

Haysey
December 22nd, 2005, 04:57 PM
Best Post in the oldies section for a while.....


MIKE ARE YOU TAKING NOTES!!!!! your guage might work right before u sell er

Inline5
December 22nd, 2005, 07:05 PM
My V8 too has the temp gauge bolted to the cluster, but even though I'd pulled it apart I never thought to sand the connections. Nice one.

Wayne90Q20V
December 22nd, 2005, 07:07 PM
Impressive work and competently compiled body of knowledge.
I dips my lid to you!

Wayne in awe

Love/Hate
January 22nd, 2006, 09:55 PM
After my initial excitment of finding this forum nearly a year ago, which soon turned to disapointment the more I read of peoples problems and the lack of help they recieved, I gave up reading. I recently had another look and decided to write.

Brilliant post. If there was more posts like this people wouldn't make expensive mistakes (and most don't know they are mistakes) and pay a ****e load of money for a 'specialist' to do nothing but rip them off. After my Audi 'specialist' ('hardings' of Brisbane) experience I have done all my work myself. A $6000 quote from them cost me $500 to do. Why? An example, a $135 multifunction sender unit wasn't the problem for my temp. gauge, a dirty contact was and things like this. When you hear 'its a common problem, try this'. Ask questions. If it is a common problem, why don't they fix it, not try something. If its a sender unit or anything else, they can test them. You don't need to replace it to see.

Anyway, my 80 has notched up 200 000 klms, it has now got more power, better fuel econemy, new interior, a nice sound system and everything works! How much? The stereo was by far the most expensive. I hired a new Astra the other week, take my 12 year old Audi any day.

liferider
January 22nd, 2006, 11:01 PM
just a question, on my 80, the first 2 warning lights flash when i have the key turned so that it has contact, is it supposed to be like that? they turn off after the car starts. the water light comes on sometimes when the car hasnt been more than 20mins and if i rev it past 2k

Blitzkrieg
January 23rd, 2006, 07:24 PM
Oh man, i could kiss you right about now. You just saved me $200.

FIO
January 25th, 2006, 06:10 PM
thanks mate. my light behind my digital clock in the dash has blown. is it an led behind that? and can i access it if i get the instrument cluster out?

thanks

Kristian

arcane
February 2nd, 2006, 01:37 PM
Hey guys - glad I could help.

@FIO: I can't recall the exact layout of the lighting for the the digital clock, but based on the fact that the dimmer works in-conjunction with the digital clock, you could pretty safely assume it would be a bulb.

@Blitzkrieg: I'm glad this was of use.

@liferider: The warning lights in the cluster-of-four at the top? The top two (coolant and brakes) flash as part of the warning-light test sequence. As for the water light, it's a tough one. Assuming it's a low-coolant level alarm, it would likely be coming from the expansion bottle (I'm pretty sure that's where the level sensor is placed). What might be happening is that the level is a little low, and once the coolant begins to expand it resets the level sensor.

@Love/Hate: I'm glad you appreciated the effort. I'll hopefully add to this howto with a few more in the future.

@Wayne90Q20V: Appreciated, thanks!

AA003
February 3rd, 2006, 10:30 AM
. As for the water light, it's a tough one. Assuming it's a low-coolant level alarm, it would likely be coming from the expansion bottle (I'm pretty sure that's where the level sensor is placed). What might be happening is that the level is a little low, and once the coolant begins to expand it resets the level sensor.



Try cleaning the sensor. Common problem

dtulloh
February 5th, 2006, 06:24 PM
There is a globe dehind the digital clock. I just had the car serviced by Audcare at Artarmon and they replaced the globe.

FIO
February 5th, 2006, 07:06 PM
There is a globe dehind the digital clock. I just had the car serviced by Audcare at Artarmon and they replaced the globe.

do i have to take the instrument cluster out?

dtulloh
February 7th, 2006, 02:50 PM
Can't say 100% but I think yes -you'll need to take the instrument panel out. The repairer had mine out because he was also replacing the ignition switch.

Matt-Matt
February 4th, 2014, 12:13 AM
Hate to thread revive!

But I just picked up a 94 B4 today, where the temperature sensor permanently sits on the minimum and the fuel gauge kept going between empty, half and quarterish.
I am suspect to both being bad contacts, I know my old 91 B3 had the same problem and i never know how to fix it!

I will be looking at this tomorrow anyway, thanks! :D