Hey everyone!

I just replaced the heater core in my 2000 Blazer, I had put it off a little while and finally got around to it. What a job, but got it.

Now, a have a few problems, some are preexisting, some are new...

Once I reinstalled all the of the dash and plugs/wiring etc, I have one problem that isn't major but would like to fix it before I reinstall ALL of the dash trim. I have a black 3 flat blade plug left over (coming from the harness that controls the heater/AC control at the center of dash) that for the life of me I cannot figure out where it goes. I have all of my radio and heater control plugs plugged in, and checked every where for the other end of the harness that it plugs into. I really hate to take the dash back out. The problem it is causing (that I think the plug is related to) is that my instrument illumination, including all lights on the radio (clock and all) will not come on unless I turn my lights on, then everything including the radio lights come on. My radio still works fine, but no lights on it or anything else until I turn my lights on.

Another problem I have, that I think I know what it is, is that it will not shift out of 2WD, this problem has been around for a while, and before the heater core problem. When I press any of the buttons on my 4WD dash control, it just blinks and then stays in 2WD, I believe it to be the transfer case shift motor. Does that sound right?

Another question is, right at the very bottom, behind the dash trim in the center of the dash there is some type of a control module with large plugs, Brown, Blue, Purple. A little antifreeze from the heater core had gotten onto it and looks like it has slightly corroded the pins on one of the plugs. What is this control module?

Any help is appreciated!

 

Anybody?

 

Maybe a picture of the locations you are inquiring about..?

 

3 wire flat plug guess: did you plug in the actuator motor? Goes into top of heater box in back of the glove compertinent.

 

I'll try to get some pics to help.

And I believe so Ron, this 3 blade plug is right off the larger harness that runs the AC/Heat Temp Control and the Radio, coming off of that harness it is only about 8-10 inches long.

 

The module with the 3 colored plugs is your body control module. A picture of the mystery plug would be helpful or the colors of the 3 wires.

 

Ron, thanks on the BCM, I thought that's what it might be after the fact.

I will get some photos, I simply need to pop the outer most trim and pop the radio out again and can get a photo of the plug/harness.

Thanks.