HVAC and rear blower failed, back after fuse replug

Dadwagon

Original poster
Member
May 21, 2020
141
West coast
I finished a successful 500 miles road trip with the A/C blasting through up to 108f temperatures. A couple days later I go to turn my HVAC system On and the rear blower won't turn on. The power button on the rear blower just cycles the OFF message on the screen. Next it turns out the A/C lines are hot and we have no cold air. Long commute home with windows rolled down in 89 degree temps. Turn off the car, without unplugging battery, and remove all HVAC fuses including the solid state BIG one. None are blown. Turn the car back to ON position with motor off, give it a minute or two, external temperature reading 117f, ouch those are some hot engine temps, coolant at 190. Turn on car, rear blower and cold A/C is back to normal. All the light bulbs are working, I thought that would cause the HVAC to fail as a "reminder" but nope.

What does this mean? Where did this gremlin come from?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Was it just your rear HVAC that wasn't working or the whole system? I assume that you say you have an OFF message you have an auto system and not the manual system with the sliders? If that's the case, maybe the HVAC module/display is starting to fail. They don't fail often but it does happen. If you have a PnP nearby, maybe just grab another one and swap it out. Be sure it's from a same year LWB.

If you need to reset it again, you only need to pull the HVAC-B fuse. Put the fuse back after about 10 sec, turn the key to RUN only and let it do the relearn.

Edit: Just looked up your profile and it says 04 Rainier which is only SWB so get a module from any 04 SWB. Your rear blower only pulls air from the front system through the center console so it's really just a single system unlike the LWB trucks. Same reset procedure.
 

Dadwagon

Original poster
Member
May 21, 2020
141
West coast
My A/C system including rear blower has been back to normal since pulling fuses and putting them back in, it's been good for over a week. Yes it's Does this mean light corrosion on the fuses could have tricked the system into failing? Confusing why this happens.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
It's possible or it just needed a reboot. Keeping fingers crossed 🤞
 

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