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Extra HVAC plug?

zenoreilly

Member
Messages
7
Location
Illinois
This thing added an hour of frustration labor time to my radio swap. There are 3 plugs for the HVAC stack: Blower motor control in the center, and one each for the thermostat and blend-door. The blower-motor plug doesn't resemble much else behind the dash and certainly nothing in the center console. The other two however are very similar; so much so that the back of the trim panel where the plugs actually go has the color stamped near it (one's black and the other's gray). The other plug in the multi-pin family is for the 4WD and looks mostly similar but a 2nd glance is all it takes to show a difference.

So while refitting the panel I reinstalled the plugs from bottom to top to avoid switching the HVAC twins, and when I get to the top I'm mostly doing things by feel because everything else is connected already. The hazard-lights plug is a no-brainer and the 4WD plug is all that's left...except this time it won't go in. Okay, maybe I have it upside-down? Nope, I was right the first, third, fifth, and seventh times. Try as I might I could not get that thing to go. I finally got fed up at what should have taken maybe 5 minutes and disassembled it again only to find this:
IMG_20220501_190710.jpg

Looking at them directly the difference is obvious, of course. The one on the right is for the 4WD and the one on the left is, apparently, the gray HVAC plug's evil twin? I was trying by feel to plug that one into the 4WD control which is obviously a no-go but not so obviously if you don't know this other plug exists.
IMG_20220501_190734.jpg

This pic wasn't the best angle and I'm not taking my dash apart again to redo it but if you look at the bottom of the pic you can see the other two HVAC plugs. My H3 came with every option available except backup camera and remote-start. I can't find any place there would be dual-zone climate controls even if it was available for the 2008 model year. I had the blower-motor recall replacement done but that shouldn't have anything to do with the blend-door control. I don't have any I-never-got-around-to-it things not working in the truck and no behavior that would be explained by simply needing to be plugged in.

What the hell does this thing go to?
 
Last edited:

650Hawk

Well-Known Member
Messages
377
Location
SoCal
I'm not sure what you're asking. The HVAC control module has 3 plugs; black, gray, and red (in the center). The transfer case control module has 1 plug. If all 4 of those are plugged in and you still have an extra plug, perhaps you looking at the stock radio plug?

No, there is no dual zone option. And I'm not sure why the avoidance of removing the dash to clarify things. The center (silver) dash panel pops off easily with no tools and will expose everything you need to see.:huh:
 
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alrock

El Diablo
Staff member
Messages
10,051
Location
Scottsdale
Have you looked at the items that you pulled from the H3 to see where those could fit? I too suspect it belongs to the stock radio but I haven't pulled that out in years.
 

deserth3

Well-Known Member
Messages
1,055
Location
Layton, Utah
Pretty sure the plug with the gray tab went to the oem head unit. If I remember right that is the speaker plug.

Sent from my SM-S906U1 using Tapatalk
 

zenoreilly

Member
Messages
7
Location
Illinois
After entirely too much digging in boxes of crap (that will now mostly go to the curb), I did find my OEM radio and it does appear to go to that. For context, it wasn't the stock radio that I was taking out at this particular time; I yanked that junk some years ago and replaced it with a JVC that has now found a new owner. I have everything head-unit-related going to an interface box to keep the door chime and whateverthehell else is supposed to run through the radio and forgot there was a separate plug that didn't go along with that; I don't think it's speakers as I have those wires accounted for.
 
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