sadik007

Hi all

Continuation of previous problem
https://forums.audiworld.com/9080/msgs/398349.phtml

This is ongoing story with my car (Audi 2.0 B4 1994 80 Avant Q) and engine running hot. Temperature in city type driving would go to 100+. Then 3 speed fan would turn on and drop it back to 100 and so on. Way to hot. Strange thing was that on open road temperature would drop to below 90. When I shorted thermo switch plug bought of fans speeds worked. So this has been driving me crazy for last 3+ months. A lot of parts have been replaced.

Long story short. I finally have discovered something strange. If AC is ON the engine temperature is back to normal even in heavy city driving. I figure it must have something to do with fan relay, just cant figure out which. Because when I turn on AC I can here click sound in relay box next to my feet. I have tested all this week and as soon as AC is on temperature drops down to normal, as it use to be before.

My question.
Is it relay and which one. Where is it located. Also, what is number on it.

THanks

4Driver4

Have you checked/changed the thermo switch? If you jumped the wires at the switch and the fan worked correctly, it's more like a switch problem than a relay problem...?

sadik007

not a long a go I replaced TermoSwitch and termostat. Plus pump is almost new.

Termo switch controls 2nd and 3rd speed. Right? But there is 1st speed as well wich AC uses, plus after run as well. But AC also uses 2nd speed?

4Driver4

Low and high. When AC comes on it kicks the low speed on; when AC pressure gets extremely high it turns the higher speed on. Coolant temp switch can do either depending on temp.