Over heat

[niteshadw]

I have a 1991 Audi 100. The car's fan's have two phases but they only turn on once the red over heat lamp in the car turns on, I was wondering if anyone knows what would cause this to happen; what controls the temperature. Also, if anyone knows the location of radiator fan motor resistor.

Thank you.

[stv840]

if fan dosn't run in high ck thermo switch located botom right of radiator ohm it out should turn on at 190-200 deg F if ok ck relay # 7 botom left in axsilery box under drivers steering wheel panel most likely thermo switch resistor may be integrated in fan not sure but can ck