I have reviewed a number of groups and postings and am more confused than ever. About a year ago the fan speed on my 2000 V70 started to quickly cycle fast/slow even when set to wide open. I put another used ECC module in the dash and it did exactly the same thing. I think that rules out ECC failure.

Now the fan does not work at all. I suspect it is the fan control module (FCM) because of the earlier symptoms. But I have no voltage to the fan, even when the fan is set to wide open (slider to the right). I have read that the FCM is bypassed when fan is set to wide open. If this is true then no voltage is leaving the FCM which would lead you to believe it could be the fan, or both fan and FCM. The fan has only two wires, yellow/purple and solid blue. If the FCM is bypassed it must be internal.

I should test the fan off the car but which is the positive wire?

To make matters more confusing while testing for voltage to the fan the red led's on the ECC module began to flash and now flash whenever ignition is turned on. Any help or thoughts are much appreciated. I am pretty handy mechanically, but not with electronics.

Thanks to all
Gene

2000 Volvo V70
126k -- barely broken in