I just got a 1997 Chevy Blazer with the switch on the dash near the center vents to select 2WD/4HI/4LO.

None of the lights on the selector switch work and the 4WD does not work either.


After a lot of searching online, I have finally found the wiring diagram for the TCCM circuitry. I can now confirm that the lights for the 4WD selector switch are powered from the TCCM. I can now also confirm that the TCCM itself is mounted behind the ashtray/lighter on my 1997 Blazer.

I have verified the wiring to the best of my ability and everything appears to be in good nick and proper. The one thing that I am missing, and it seems to be a major component of the 4WD system, is that I do not have +12V available on pin C8 (Should be hot in Run and Start).

The wiring diagram I have shows that this wire gets power through fuse #4 (Gauge fuse) and I have verified that fuse is good and there is power to it. What I cannot find are the two junctions shown in the wiring diagram S213 and S241. It seems to me that a break in either of those will kill the power to the TCCM and disable my 4WD.

Does anyone know for sure where those two junctions are located? I don't want to tear apart the whole dash searching for them, nor do I want to just wire around those junctions. I would prefer to find and fix the break in the circuit.

Does anyone have any help, experience, advice on how to proceed?


http://i262.photobucket.com/albums/i...CCMCircuit.jpg

 

Do you have battery voltage on the pink wire at the front axle engagement switch with the ignition in the run & start positions?

Edit: This will help in locating the open circuit.

Also, all "S200" series splices are in the main dash harness. The only place to find exactly where in the harness the splice is located, is in a GM "dealer issue" shop manual for 1997 S&T series vehicles. Ebay sometimes has them.

 

Thank you for the reply. I will check under the hood for a possible break in the wiring. I will also watch eBay for a GM shop manual. Last thing I want to do is start hacking into the wiring loom blind.

 

Here's a link to the same '97 dealer manuals I have. You might find them for under $100 on ebay, but if you need them in a hurry, this where I buy some of my manuals.

1997 S-10 Sonoma Jimmy Blazer Bravada Repair Shop Manual Original Set of 2

EDIT: Actually a much faster and cheaper way is to buy a subscription for your vehicle to alldatadiy.com It's only about $25.00 per year. Unfortunately I do not have a way to scan the pages in my '97 manual for you. All I can tell you is S241 looks to be inside a loom in front of the driver up in the dash above and to the left of the bake pedal(?). S213 could be in a loom higher than that more in line with the steering column. Hard to tell without looking at the wires myself.

 

Check voltage on the pink wire, (ignition in the start or run position) at the axle engagement switch. Component #18 in the diagram:



The results will give a good indication where the problem is.