Radiator Fan permanently on

andya · 07-03-21, 01:41 PM

Hi all. Went to take the CQ out today, ignition on. The fans on. And it won't switch off. I've checked all the relays and fuses bar 1 which I don't have a spare of - part number 813906064 this one sits behind the glove box on the passenger side and the base appears to be a little loose. Yesterday whilst moving the car around I could have sworn I heard a relay clicking from that direction. This morning I have also checked the relay for the rad fan within the fuse box. Nothing's made any difference. I've even tried swapping over a fan motor and it made no difference.

Does anyone have any ideas or whether the relay I can't replace would be the one?

It's a 85' kv coupe quattro.

Many thanks in advance

Isimmo · 07-03-21, 02:09 PM

With the ignition on and fan running erroneously, lay underneath and gently but firmly ‘whack’ the thermostatic switch on the bottom tank of the radiator.

I’ve used a set of mole grips regularly on ours before it was replaced.

andya · 07-03-21, 05:45 PM

Many thanks Ian. That's worked a treat! I'll have to replace that sensor. Many thanks again

07-03-21, 02:09 PM	#2
Isimmo Super Moderator Classic Audi Club Member Join Date: Jul 2007 Location: Sissix-by-the-sea Posts: 15,218	With the ignition on and fan running erroneously, lay underneath and gently but firmly ‘whack’ the thermostatic switch on the bottom tank of the radiator. I’ve used a set of mole grips regularly on ours before it was replaced. __________________ 1985 WR quattro, 1985 20vT RallyRep, 1993 MTM ABY S2 Avant. 2010 S3 Sportback. Last edited by Isimmo; 07-03-21 at 02:13 PM.

07-03-21, 05:45 PM	#3
andya Senior Member Classic Audi Club Member Join Date: Aug 2010 Location: Hampshire Posts: 1,149	Many thanks Ian. That's worked a treat! I'll have to replace that sensor. Many thanks again __________________ 1985 Coupe Quattro 1986 Coupe 1.8 weber carb 1987 Coupe 2.2 GT