Do not fully understand, are you are saying when the FBH fuse is inserted the FBH fires up and runs, without being started by the temperature sensor or a remote switch, or does the air fan run continuously. If the air fan runs continuously and does not stop intil fuse is pulled, then there is a air fan short circuit on the PCB, This will not be a resistor fault, because I have yet to test a resistor that fails closed, they all fail open circuit.
If the FBH actually fires up and runs, diagnosis is simple without a meter. Remove the wire from pin 3 at the switch, if ok fit another switch. If the same, remove pin 3 of the 6 pin connector, if ok, replace the wire to the switch. If when pin 3 is removed the FBH starts and runs, remove pin 1, if ok, it is the sensor, although unlikely.
__________________
If at first you don't succeed, hide the evidence
|