HVAC, Temp Control Loss... I am SO PISSED!

[Waterloo]

As you all know, I have poured enough money into to my 2008 POStar HVAC system to buy an island next door to Bill Gates, and have a few bucks left to litter my yard with nicely restored Petes...

I have also contacted a few supposed experts at International... Don't waste your time, as they are either to young, and or don't have a clue or give a shi#t. But they will never admit it, just their best guess? You are on your own. Welcome to my world... And many others here... Sadly.

Anyhow...

I fixed the continually failing blower motor issues with this harness/resistor, http://rawze.com/forums/showthread.php?tid=1390. Here is the OEM part number for this harness... 3865234C92

That works, thank GOD.

New issue, no temp control. Blowing cold air in the dead of winter, just like in the summer, hot air! And yes, I inspected the blend door, it moves freely and shows no signs of damage. The in dash monitor shows that my Temp Actuator is jammed or broken, not responding... So, the body controller is throwing a code. So, I figured a blown actuator, very common, so I went and bought one today and installed in the dealer parking lot... In between loads, took 20 minutes to swap and I was rolling... Bad move, it was not the actuator...

Anyway, the temp control actuator is not getting power, AFTER I installed the new harness with the resistor... I pulled everything apart, AGAIN! I pulled the harness to the blower, power module and actuators... I put the meter on the harness to the actuators and the juice is flowing. I pulled the jumper harness with resistor, good continuity. No issues there. No power coming from the HVAC control in the dash to the new harness. And yes, I tested both actuators, they both work.

Prior to that, I have yet again been pissing money away replacing blown parts. In the hunt to get my blower motor working, I also replaced the HVAC control module, the three dial unit you use to control your HVAC system in the dash.

I have been chasing wires, brought up the schematics, Navistar Bodybuilder... http://bodybuilder.navistar.com/General/...s08339.pdf

There are 13 wires in the harness that attaches to the HVAC control unit in your dash. There are four wires that go directly to your two under the dash actuators, heat control and where it comes out, floor, defrost, etc., along two more that go to your recirculate door actuator in your engine bay. These are direct feeds off of your HVAC control in the dashboard.

I believe that the HVAC control unit in the dash has taken a dump. International remans these HVAC head units, and I think I have a bad one. Everything was fine in regards to hot and cold, until the other day...

Alright, just took the brand new, from a few weeks ago, HVAC head unit out of the dash, the unit you control your AC and heat with, with the three knobs. I pulled the HU and removed the plug from the back of it. I used my meter to test continuity of the wires running to both actuators, the wiring checked out good with all of the harnesses connected, it is not the wiring.

The new HVAC HU seems to be the issue. I will replace tomorrow and get back with the results. What a PIA, and it is my birthday to boot. In the garage, drinking beer with Sam, my little buddy. To bad I cannot get the truck in here, snowing out there right now... Freezing my ass off, thank God the garage is heated, and the beer is cold. ;-)

I will amend in the morning when the I get the new HVAC HU from the dealer... I hope this helps someone.

[pearce trucking]

I know this is the obvious, but I have to ask? Are your heater lines supplying hot coolant to the heater core?

[Waterloo]

(01-28-2017 )pearce trucking Wrote:  I know this is the obvious, but I have to ask? Are your heater lines supplying hot coolant to the heater core?

Yep, that was the first place I checked, because that was exactly how it all "felt" in the cab. Like someone had turned off my heater line. I pulled the HVAC HU and there was no signal going to the actuator according to my multi-meter so I believe I have this issue solved...

[Waterloo]

Just got back from the dealership... Drove the truck up there and tried out the new HVAC head unit, it works. Problem solved! Putting it all back together now... Getting old.