My fan on an 945´-98 with AC.
Its working even if the ignition is turned off. Too stop it , is to disconnect the battery. A have changed the the reley for the fan. No help.
What the next thing to check ?

is there any tempgauge somewhere that gives a signal to start and stop and if there is where is it located ?

Ulf L

check your thermostat. A faulty thermostat was the cause of the same problem I had on the 965. Put a new one in and it solved the problem.

Hope this helps.

Mike
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Mike Brown Greenville, NC 1996 965 105K 1994 940 135K 1986 244 137K

the thermostat is mechanical and in the engine block, immersed in coolant.

the thermoswitch is in the radiator, immersed in coolant.

The thermostat controls coolant flow from the engine to the radiator...engine/coolant gets hot, thermostat opens to allow hot coolant to flow from the engine and cooled coolant to flow from the radiator to the engine.

The thermoswitch activates the radiator fans to move more air through the radiator when the top of the radiator gets warm enough to cycle the switch.

Not unusual for the thermoswitch to fail closed...in fact, you WANT it to fail closed vice open because if it fails closed, the worst that happens is you overcool the radiator or kill a battery. If it fails open, you risk overheating an engine in slow traffic and potential engine seizure.

Nope, I mean thermostat. If the thermostat fails and the engine runs too hot then this triggers the fan to keep running even after the key is off. Of course, the thermoswitch would be another possible source of the problem.

Mike
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Mike Brown Greenville, NC 1996 965 105K 1994 940 135K 1986 244 137K

If the thermostat was not opening (as you are suggesting) then his primary problem would be overheating when the car was running. The cooling fan continuing afterward would be nothing more than an after-effect.