The cab heater/air con fan on one of our 57 FHs seems to have a mind of its own.
With ignition off and heater fan switch in off position (does it also with switch in auto tho) the fan will randomly switch itself on and the only way to get it to stop again appears to be to switch the temp control to cold and fan then stops. You have to remember when parking up to switch fan off & temp control to low or batt probs occur.Volvo say as its intermittent and they are unable to get it to do it they are stumped.
Any ideas appreciated 
it will be one of two things
- the fan switch fault
- the common part known as the hedgehog which is a resistor mounted on the fan motor, it’s a take the n/s foot well to bits and unclip the heater box and slide the motor out
when this part fails the fan motor can run flat out even with the key in the off position, and also the same part gets v hot!
moose
green456:
The cab heater/air con fan on one of our 57 FHs seems to have a mind of its own.
With ignition off and heater fan switch in off position (does it also with switch in auto tho) the fan will randomly switch itself on and the only way to get it to stop again appears to be to switch the temp control to cold and fan then stops. You have to remember when parking up to switch fan off & temp control to low or batt probs occur.Volvo say as its intermittent and they are unable to get it to do it they are stumped.
Any ideas appreciated
Got the same on my 07 fm12. Its the climate control, coupled with the night heater trying to use the heat from the cooling system to heat the cab with the n/h running. All it does is keep putting fan on full every few minutes, does ya head in!! As said turn fan to cold and all ok. HTH Dazza