[sspeer]

Just bought this truck, drove it on a hot day so I didnt notice the heat didnt work.
I checked the vent door and the motor( the one above a passengers left foot)
I felt the top of the heater core and both hoses are hot
The engine temp is normal
All the swithing of vent selections are working
AC works fine, max and normal
The temp control for ac is also working.
Signed, Baffled

 

[ModelTFan01]

I don't know much about auto air conditioner's and heaters, but I'll take a stab at this.

Have you checked the air mixer mechanism? (Sorry for the laymens term. What I'm talking about is that mechanism that allows it to mix the cool and warm air.)

If that isn't the problem, check the relay that is in between the control knob and the air mixer mechanism motor. That relay may be going bad.

I'm sorry if I'm no help. As I said, I'm excellent at house-sized (residential) climate-control units for my age (13 years old), but terrible at automobile climate control equipment. Both are so different yet the same.

Sincerely,
Garrett :wavey:​

 

[sspeer]

Thanks, I fix copiers for a living, so Im familiar with electrical control systems etc...
Heres what Ive done since my first post.
Talked with several mechanics, one did a system test to see if there were any motor errors(blend door, vent switchin etc. I pulled the blend motor, checked the coupling and manualy moved the door back and forth. No heat still.
I flushed the system,flushed the heater core with CLR(soaked it for 35 minutes) using some hose adapters that I made, flushed both ways at least 5 times. Last thing I did was replace the thermostat. I have to wait 24 hours for the gasket sealant to set, then I will fill the system with just water and test. The engine seemed to be running cooler than one of the mechanics I talked to would like, so thats why. I will post results tommorrow.

 

[sspeer]

We have heat, she's cookin' now! Pretty sure it was gunk in the heater core, lots of little chunks came out when I flushed it out.