Group 44

My friend has a 93 90s with 67k and the rad. fan does not shut off. Is there a run on fan switch that i can look for on his car.....

thanks in advnce!!!

quattro.pilot

under the hood. A V6 does not have an after-run fan function IIRC. Fan activation is also linked to Air Conditioning on/off via another relay, so you may want to pull that one too.

Yanking the relays should ultimately make the fan stop no matter what the problem is. If the relays unstick themselves or else test good then the next major suspect is the temperature control switch in the bottom right (passenger) corner of the rad. There's a connector (3pin) you could pull to see if its disconnect stops the fan. If it does than the switch has failed, if not than it's likely an upstream problem @ a relay.

hth

Group 44

heading over to his house to give him a hand.......

quattro.pilot

the ignition. Or is it the case that @ Pre-start or engine running, as soon as there's power in the car the fan starts spinning. This aspect could narrow down the potential causes.

Does he have a Bentley do u know?

dassub

I've tried pulling the one that's labelled a/c relay, and it doesn't kill the fan. Any thoughts?

quattro.pilot

with an electrical connector (2pin Red) on one end of the a/c radiator. It's the switch that forces the fan to run when u activate the a/c. I don't know exactly where this switch/connector is on a B4 (even though I own one, ha.. i do know where it is on a S4), but if you can find it that'd be a way of disengaging the fan-a/c circuit.

I assume you've tried pulling both fan speed relays but to no avail..? The A/C high pressure fan switch is *supposed* to only trigger and be wired with the High speed. So theoretically if u pull that relay the fan shouldn't work with the A/C. Just another trick to try in case you hadn't already.

dassub

It won't come on, which is good, but the high speed one only comes on at about 100 degrees, which sucks because it only comes on and then turns off a few seconds later, leaving the car at +90 (around 100 still), which isn't really that great an option. (that was way too long a sentence).

audiPete

if the fan stops, then you know what you need to do ;-)