I believe my electric auxiallry fan on my 91 Volvo 245 SE is not working correctly. I replaced the black relay with a used one because it was not turning on at all wehn the A/C was on and it was working fine but now it does not cycle on and off like it should and my car starts to get hot especially at idle. It will not overheat with the A/C off at idle so I know it's not a bad fan clutch. Car also has brand new radiator and thermostat. Temp gauge works fine. Coolant is brand new and mixture is proper. I really believe it's just my auxiallry fan but here's the weird thing, there is no temp switch in the new radiator and there was never a temp switch in the old one either...So my question is, is there always a temp switch and a temp relay that controls the auxiallry fan or can they only have a relay? I heard someone say that the fan turns on when the pressure is high enough but I always thought it was by temperature and the temp switch kicked it on when it got hot enough? Also,could there be another location for a temp switch other than on the side of the radiator or do I just have another bad relay? Thank for your help

 

See:
http://www.brickboard.com/RWD/volvo/..._question.html

It is controlled by a high pressure switch.

 

Hi Thanks for your response. Actually, I found the correct answer. My friend owns a Volvo shop and he told me that some later model 240's A/C auxillary fan is controlled by a relay I also verified this through my local Volvo dealer. It is actually the same set up they use on the 940. It is a larger black relay also known as the radio noise supressor relay/radiator fan relay. It is located under the hood posted on the drivers fender. The older model 240's usually always used a radiator temp switch if they even had an auxillary fan but most do not. How it is supposed to work is that when the A/C switch is in the on position the auxillary fan should come on and stay on via the relay. If the relay is bad it will come on then turn off come on turn off etc....I have a bad relay.