Radiator Cooling fan doesn't come on

bergerdon · Post by **bergerdon** » 15 Aug 2012, 23:51

1996 Volvo 850 GLT relay cooling fan2-spd 1398845
How would you test this relay?
The car overheats at idle/ Fan does not come on. I have tested the fan and both speeds work. The red single wire carries battery voltage. Do the 2 pins/wires (yellow and White/yellow) from the engine control module carry any voltage? When engine is hot , there is no voltage at the 2 fan pins ( out 1 & 2 on the relay)
Don

Post by **Ozark Lee** » 16 Aug 2012, 21:56

The fan relay is controlled by the yellow wire and the yellow/white wire - one is high speed and the other is low speed. Try grounding the relay contacts, one at a time, associated with the yellow and the yellow/white wires and see what happens. If you still have no fan the culprit is likely the relay itself.

...Lee

bergerdon · Post by **bergerdon** » 19 Aug 2012, 22:25

Thanks Lee,

I have tried the grounding of the 2 wires y & w/y and they both turn on the fan. I tested with key off, engine cold. Where else could the problem be?
Don

Post by **taxi** » 20 Aug 2012, 03:21

Hi, are you sure it is overheating? Maybe there is a leak preventing the cooling system from building pressure, or something else?
I know mine doesnt turn on fan until its quite a bit over boiling point, and without correct pressure it would likely boil too.