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1999 VOLVO Turbo 2.8L S 80

Cooling fan runs continuously, even with ignition switch on. Volvo dealership diagnosed it as a bad “fan relay”. Over the phone Dobb’s says it is the “cooling fan motor module assembly”. RemcoW has been patient enough and good enough to send me some very good information. But i am still wondering how to trouble shoot in order to determine OR . Can not find relay and it is not in manual. What do you think about, with motor and fan running, pulling relays until I find the cooling fan relay? And then substituting one of the other relays in the box and see if the fan quits running when temp is satisfied? Any electrical problems doing that? Any suggestions?

I don’t see a problem pulling relays, but I suspect the relay in question isn’t in the relay box. Likely your trial and error will come up empty. The relay could be part of the fan assembly. Point of the relay is to use lower current to the sensors and ignition switch. The wiring can have a heavy duty wire going into the motor assembly to provide high load power to the fan, and the small wires in the assembly are more likely connected to the relay.

If you can buy the relay separately, once you have it you might have some clues as to what to look for to find the old relay. I’d look for the relay to be very close to the fan motor.