Hi,

I am a newbe in the Audi World. (driven before several BMW's and Ford's).
I have buy'd some months ago an oldAudi A4 B5 (1995) with a AEB 1.8T engine.
Now I have serious problems with this car. Most of the times he wouln't start. When I push the car, he starts directly. The starter wouln't be activated. I have buy'd a new starter (and also a new battery)now, but I still have the same problems. Sometimes I hear a click from the starter, but that's all.And ... sometimes it works fine!Whatcan this be?
The immobiliser works fine (start contact powered and no errors readout with vagcom)
Also the climate control is going crazy. After switching on the contact, the display blinks with an interval of +/- 1 second. It is possible to control it. But.... it only blows very hot air and only through the ventilation openings in the middle of the dashboard, not possible to control it. No air on the window and on your feet.
Also the powered windows does not want to rise up completely anymore.

This errors come together at ounce. Doe anyone knows what this could be?

I hope so, cause this car drives me really mad. (Already had a defective airco compressor, a window that was broken down, central doorlock that stops, wastegate broken, a lot of rattling sounds are coming from the front wheels last month etc.)

Thank you very much!

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Audi A4 problem-car

Nobody?

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Audi A4 problem-car

Starter problem found! Badground connection between the engine and the car chassis! Oxidised connector was the problem. I have installed a new wire and have cleaned up the connection points and now is starts perfectly!.

But ... still problems with the climate control unit!

Someone knows a solution? A reset possibility or so?

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Audi A4 problem-car

sounds to me like a bad control box. given the age, it's common for the contacts to pop from the board and cause lighting, control, and sometimes random problems with the digital control boxes. Pull the box, and open it up taking a look at the PCB inside. more common than anything is the ribbon cable plug to lose conectivity. i have nearly 1/2 the pins on mine that needed resoldered. if you have a heatgun sometimes you can heat the board and "rewet" the connections... be careful not to trash the board... soldering was easier for me but i solder mirco connections alot.

just a tip that hopefully points you in the right direction.
-Ryan

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Thank you for your reply. Soldering -also SMD- is not a problem for me.

But what is the control box? Where can I find it? Behind the AC display or so?

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Audi A4 problem-car

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Audi A4 problem-car

http://www.audiworld.com/tech/elec153.shtml

Here's a DIY how to on it. this is for the ribbon cable socket, but when you're in there you'll see the contact points for the buttons. i used a soft pencil eraser to clean the contact points on the board. My unit was almost completely non functional, no lights on the display, buttons working 1/2 the time... i thought it was a lost cause. it now works 100% everytime, all the time.

Good Luck!

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If your not to comfortable soldering the contacts yourself, there is a guy on ebay that will take your control box, fix it, and send it back with a three year warranty if anything happens to go wrong with it. Its exactly what i did when i first got my car and it ran me just around $100 warranty included. Just search for a new box and he should come up.

Old soldering


Soldering refurbished


Vag-Com status readout


Vag-Com reading another module in this car

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Audi A4 problem-car

Hi,

Thank you for your replies.

I have opened the AC unit today, the solders on the display module are "resoldered" by an amateur. I have resoldered them (see pictures below) and checked them, but still the same error! I have tried to read it out with vagcom but vagcam gives errors, see picture below. (every other module in the car is possible to read with vagcom).

Does anyone have tips for me, what can be wrong? Or maybe a connection diagram of the AC unit. Maybe I can find out with these information what is wrong!

p.s. the type number is: 8d0 820 043 D & 5hb 006 500-11 (HELLA)

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Audi A4 problem-car