I've got a 1991 Legacy that is having some intermittent trouble with the HVAC fan.

 

Whenever I start the car and the HVAC system is already selected some kind of ventilation, I have no trouble with the fan or temperature controls. All temps and all fan speeds can be switched back and forth.

 

Whenever I change to a different HVAC mode (such as switching from Max AC to regular AC) the blower fan will frequently cut out and will not be able to be restarted until switching the HVAC system off for several minutes. Sometimes the car has to be completly shut down for several minutes before the blower fan will restart. This problem started several months ago, and has become more worse as hot weather has set in and the air conditioning was used more and more

 

I took the vehicle to the dealership where the technician replaced a fan relay and cleaned all the contacts and circuit boards inside of the HVAC button selection panel. The technician told me that the climate control module needed to be replaced, at a cost of $320 for the new part. I got a used one on Ebay for $50, and this used part did not fix the problem - the same symptoms immediately occur. I took the circuit board out of the Ebay purchase, had all of the solder joints re-soldered, put the HVAC module back together, and after install the same problem still occurs.

 

Does anyone on this message board have any suggestions, perhaps from experiencing the same problem? The dealership technician did a lot of wire tracing and found no short circuits or loose connections. He noted that the blower motor appears to be newer, but I suspect that even if it is a newer part it might have some intermittant fault inside of the blower that is not detectable. Anyone think they can help me with this problem? I don't care now that it is summer time - being without AC I can handle. But I really need to have this fixed before winter, because I simply can't be driving a car where I cannot switch between the defrost modes to keep ice off of the windshield.

It almost sounds like its some oddity in the HVAC head unit itself. Get one from a junky and see what happens.

 

 

nipper

It almost sounds like its some oddity in the HVAC head unit itself. Get one from a junky and see what happens.

 

 

nipper

 

I already detailed that in my original post. The HVAC head unit purchased from Ebay did exactly the same thing, and after resoldering the connections in the circuit board the problem still remained.

 

Aaron

I have something similar happening to my 90. Blower won't be on in Heat or heat defrost mode. When selecting to defrost blower comes on. Also blower will be on in vent air and max air. Then after a while if put to heat it will come on. If left on heat after a while it will start blowing. Also sometimes when on aircondioning it will vent the air out the defrost and heating vents rather than the vents in the dash. This can be a pain legs get cold and the rest of you is hot. I haven't tried to do anything to fix this yet.

 

cjt

I already detailed that in my original post. The HVAC head unit purchased from Ebay did exactly the same thing, and after resoldering the connections in the circuit board the problem still remained.

 

Aaron

probally the one from ebay is just like yours BAD .THIS IS YOUR PROBLEM. ED