My heater is not working how do I know if its the thermostat or heater core? I also think the AC wasnt workin well but didnt pay much attention since the windows were down all summer. It is 15 degrees here now and cant even clear windows, so I definately noticed the heater prob.

 

Welcome to DF. Moving to the correct section.

 

What does your temp gauge have to say?

 

Do what you will with it but I haven't had heat for years. I've changed my stat twice (the first was for the heck of it. I had it all pulled apart anyways The second time was due to a defective one).

 

Had someone kinda take a quik look, and they said looks to be the switchs/controls or wires. Everything else seems to be functioning and would affect AC also.

 

I've read many of the threads on "no heat". As of 30 mins ago, I also had no heat. But I took off the blend door motor and changed the door position by hand and now I have heat. So, fortunately, I am able to skip the flush for the time being.

If you are 1999 or beyond, you should have the blend motor instead of the cable, in which case it's easy to check that first before getting into the core/flush thing.

 

My truck has never had heat in the 3 years that I had it. It is really cold here now 0 to -5 degrees, so last night I got on here and u tube and saw a video about flushing a heater core with compressed air. Also using CLR on the heater core. The video was from a mechanic named Eric.

I have a laser temp gun and before flushing the heater core, my vents were only putting out around 62 degrees. After flushing, a very comfortable 140 degrees. Took about an hour to do... But so worth it.

 

Also I am not sure of what PSI you or anyone should use but I ran mine at 40 psi and didn't have any problems, but use at your own risk, older and more fragile heater cores may not be able to take it. Then I soaked the heater core for about 10 minutes then flushed with clean water several times till water was clean and no more foam.

 

Im new here but just ran into this problem a week ago and i tried the flush thermostat and gave in and changed the heater core That solved my problem. its not that bad took me two hours and it was done.