Well, this has been an ongoing issue for me for about 2 years now. No heat on the driver's side. Super hot on the passenger side. First I tried the blend motor. I'm about 90% sure I checked it properly and it was working fine. I CLR'd the heater core. I switched the hoses to the heater core. Nothing. Finally last week I decided to bite the bullet and dive into the heater core replacement. After a large number of bad words I had it done. And guess what, STILL NO HEAT ON THE DRIVER"S SIDE! I'm basically ready to set the vehicle on fire. Anyhow I wanted to see if anyone has had this issue and can offer any further suggestions. I have 2 more options I'm going to try, well maybe 3. First is to snake the vents and see if there's some blockage like a mouse nest or something. Number 2 is to purchase a new climate control head unit and see if that fixes it. (oh, yeah, also I can't seem to get a climate control reset to happen. No amount of holding the recirc and econ buttons and turning the key seems to work). I guess my 3rd option would be to dig back into the blend motor and flap and confirm 100% that it is not that. Let me know your thoughts. Thanks!

 

You have described the classic signs of a clogged heater core. Unfortunately it is not an easy or cheap fix (depending if you do the work, or have the work done at a shop). There are some threads on this forum about this issue. As I recall, there was one guy who cut the lower dash and replaced the core without removing the whole dash (to include the steering wheel) in less than the 8 hours like the book calls for.

Hope this helps
Jeff

 

Thanks Jeff. As I mentioned above, I put in a brand new heater core and the issue persists. So it's definitely not the heater core.

 

If you put in a new heater core and you still have the problem, it is either the actuator motor on the side of the unit or the control head in the dash. Can you remove the bottom part of the drivers dash and see the actuator move as you change temp? If there is no movement it could be a bad actuator. Do you have a diagnostic tool that shows the position / voltage / percentage of temp of the control heat temp ****? It could be a bad control head.

Jeff

 

I wonder if a GAP tool can give live values on HVAC controls? Never looked. But a used HVAC control panel can probably be had cheap. Keep in mind the truck will NOT start if its missing or really damaged. Otherwise I tend to think a blend door physically broke and is stuck. FYI, the heater core is a constant-on setup, so its always hot (stupid design). So if passenger has heat, driver side of the core is hot too - unless clogged as you know, the build up occurs on the driver side cause physics.

 

Yes the GAP tool can read those values on the control head. That is how I diagnosed a bad head unit on my 2006.