The heat up front blows nice and hot but no matter how I adjust the rear ceiling mounted controls it blows cold in the back. Is this a blend door issue or something with the rear controls?

Also, on a side note, one of my rear power vent windows just stopped working too. I guess it's either the overhead switch or the motor back there. Anybody experience those going bad?

 

mine does the same thing. from what I have researched it seems to be the blend doors that would be the problem. they are located in the back on the truck under the panel the jack is located.

 

When adjusting rear controls, be sure you are using the "active" HVAC panel.
The front driver overhead control is in charge of the rear system, until you put the driver's overhead into the "rear" position THEN AND ONLY THEN do the 2nd row controls work.

 

I just went through this, check the degas bottle level. I must have had an air pocket or something in the rear heater core plumbing. I just kept burping the reservoir.
Have you had any work done recently to the cooling system? Or maybe flushed it recently? That was my case.
Keep us posted. Good luck.

 

This^^^^^^^

Must be a damn 6.0 thing...

I really don't use heat here in Fort Lauderdale, but do remember taking my freshly done 6.0 up to the mountains shortly after the work and experienced the same problem....

 

You can test the motors for free. Just pull back the passenger side panel. There are 2 motors there. Swap their locations. Now if the heat works, with no control of floor and roof, you just need a new motor.

 

No recent cooling system work. Might not hurt to try burping the reservoir though.

 

Had this problem last winter and replaced the blend door up front. It had been making noise for some time so I knew it needed to be replaced.

I flip on the auto hvac, crank it to 90 and while the front got hot. It only stayed hot unless I was driving. When I manually told the hvac what to do, I always had heat front and rear, even when I came to a stop.

In addition to the rear blend doors being a problem, my water pump seal went bad after less than a year causing a slow leak. That may have played a role, who knows?

The rear blend doors may take a little work to get to, but I'd say it's worth it if it's ***** cold out and not warm like the weather in Texas or Florida.

 

How are you making out with the coolant level?
Was it low?