Heater fan not working when cold out.

[macipusy]

I have been having problems with the heater fan on my 91 SS in the winters. When it is cold outside....below 25 or so degrees F, the motor does not work at all. As soon as the cabin warms up it will just come on. If you let the car sit outside and fully cool inside, it does not work again until warmed up.

I am thinking it is some kind of electrical connection that cracked and shrinks in the cold to lose contact, and when warmed, expands to make contact again. I could be well off though.

Any ideas where to start looking?.....relay, HVAC control unit,...ect.

[silver03]

I would start with a junkyard blower motor swap to start with and see what happens there, since all of your electrical is working.

[Legacy777]

It could be the motor itself....or could be the HVAC control panel. The control panel is known for bad solder joints.

http://bbs.legacycentral.org/viewtopic.php?f=10&t=1142

[macipusy]

My first ithought was a bad solder joint....just didn't know in which component of the whole system.

I might try to grab a HVAC unit from a junkyard and test it.

Will all prefacelift HVAC units swap over?

[Legacy777]

There are some differences in the connectors that plug into the HVAC unit. This diagram gives some more details.

http://www.main.experiencetherave.com/s ... low_up.jpg