I read through the many threads on this problem but cant find the solution to my specific circumstance. I experienced intermittent operation for 2 days then couldnt get the fan to blow air at all. The rear air works just fine when in auto mode, only the front fan wont blow. I have voltage to the resistor pack and voltage to the blower motor. I pulled the motor and tested it on the battery and motor spins fine. The fan motor doesnt blow on any fan speed, including the high setting. Votage reading at fan motor connector is 13.9 on high and 11.2-11.6 on other speed settings. Any help is greatly appreciated.

 

I remember hearing about a transistor mounted to a heat sink which will ground the end of the motor and make it spin to a certain speed.

This is usually called open collector.
Savannah knows about this device better than me...

That module may be defective for you.

 

The resistor pack is fine(mounted to heat sink). it was a faulty connector that suffered heat damage, I replaced the connector and all is well now.

 

I may also be having a similar problem. Which connector was faulty?

 

A picture is worth a thousand words...Dont have a picture available to attach, so can only offer one thousand words. There is a 2 wire connector attached to the right side of the blower fan assy (assuming LHD model). Wire colors are red(ish) and dark brown(ish). I pulled this connector, disconnected it and discovered significant heat damage to one of the spades..At some point it became hot enough to distort the connector around the wire spade. I checked for continuity after reconnecting and all tested good. I applied power to the electical system to test further and when I turned on the fan, it began to work. I wiggled the connector and was able to cause the fan to stop operating. I replaced the connector with a similar new unit I happened to have on hand and problem is solved. A cheap repair fortunately( a rare occurance for me with my Disco). If you have voltage to your blower motor, check this connector.
Good luck.