My fan works. The AC works always, but my heat only comes on once in awhile.
Where do I start? I need heat it gets cold in these mountains. I am thinking there is some sort of relay that directs the coolant to the core. How would one tet this relay? Any help would be great.

Steve

 

First thing to make sure of is your coolant level is good. Low coolant = no coolant flow to the heater core.

The blend door is electically controlled. It's a very easy task to gain access. Open the glove box, empty it out and flex the box itself so that the limiters will come out from behind the dashboard and the whole glovebox swings down to the floor. You'll see directly behind the glovebox the cover for the heater core. Remove all the screws around that cover and take it out. You will see the heater core and off to the left of that the blend door behind it. Turn the ignition on and move the heat control from max cool to max heat and see that the blend door is swinging back and forth. I'm having you do that so you can eliminate the possibility of an obstruction.
The blend door motor is mounted directly on top of the pivot for the blend door itself. On my truck it's the white rectangular box and I have no idea what it costs.

 

Thanks. The coolant level is good. I will check the blend door this weekend. I would have never looked behind the glove box. Good thing I posted here first
cause I would have been crawling under the hood for hours with a DMM.