OK, so after many months of research and days of trying all the remedies I came across, I am at my wits end! Late in the fall last year, my front HVAC blower stopped working (rear had never been working since purchase). After many futile attempts to rectify, I hard wired it to the battery and have been running it that way for about 8 months. I checked and replaced/swapped out fuses, fusible links and relays. I found none of them to be bad to begin with, but did it anyway to be sure. No result. I bought and installed a new control module, no result. I pulled the dash control panel and everything looked ok. I can control the vents and temperature fine, and even though the fan control lights up, there is no control there. When I pulled the leads off the motor, I would get 12+ volts, but that did not change with any adjustment at the dash control. I'm tired of using a toggle to control my heat and A/C, please help!!

 

My rig is in the shop and I was told that the blower motor and resistor are bad. However, when we bought it a couple months ago, the thing blew cold air and heat. So the tech told me the blower binds up.
I'll do some research. And I will try to help you out with what I find.

 

I seem to recall your posts from awhile back. I am sorry to hear that the problem has not been resolved.

It sounds like you have by now a good understanding of how the system is supposed to operate; also that so far, nothing you have done has worked, except that you now know how to hard wire the system - that is something to be proud of I would say. As such, you must have a pretty good understanding of the various circuits, both electrical and computer buss.

Given that you have tried pretty much everything, I would put my efforts into getting the rear system to function.

My first guess is that a problem with the rear is affecting the operation of the front.

You presumably have the three HVAC ***** on the ceiling re the second seat - the problem probably starts there - wiring to it from front it.

In theory, one of the buttons on the bottom right of the front HVAC control panel selects Auto or Manual operation. The Auto setting bypasses the roof mounted ***** and uses the temperatures set at the front. I would be setting the front button on Manual and then attempt to get the rear working by itself. I suspect whatever problem is affecting the rear is also the solution to the front.

Have you ever checked to see if the auto temperature control sensor located near your right knee on the drivers side behind that little rectangular grill is really there or connected? I would think the system should still operate manually without the sensor but maybe it is a showstopper.