97 Blazer 4x4 ,transfer Case Question

ScottyBoy · April 9, 2009

I have a 97 blazer 4x4 that I've been piddling with. Something seems to be wrong with the 4wd Lo gear. When I press the dash mounted transfer case switch (button) the 4wd Hi button will light up when pressed and I can hear a noise under the shifter/console area, sounds like a solenoid engaging. But when I press the 4wd Lo button the button doesn't light up steady lit like the 4wd Hi button does. It just starts blinking when I press it, and I don't hear the solenoid engaging like when its in 4wd Hi. I have no clue what do do from here or where to even look. What could be wrong and what should I look at or try and test? I'm wondering if this may be something as simple as a computer or wiring glitch or even a bad solenoid. Or then, could it possibly be a bad transfer case? Any ideas at all?

Draenor · April 9, 2009

Could be the switch, or worse the TCCM(Transfer Case Control Module).

You say peddling with, was this wrecked on the like? Have you verified the wiring?

ScottyBoy · April 9, 2009

OK, when I say piddling with, that means its my project-not my daily driver. It was my brother's blazer and he gave it to me for free (I just had to tow it here all the way fromBaton Rouge). He bought it used about 2 years ago and never even tried to use the 4wd at all that whole time. All I did was put in another switch (used switch but they said it was 100% functional and 30 day warranty). I'm still trying to diagnose every problem on this truck before I determine if its worth fixing up for a woods truck (hunting truck). I found many other problems, but now I'm trying to figure out the 4wd and see whats up with it. The last thing I wanna do is fix the cooling system, and spend $100 bucks on tune up parts, and rebuild the suspension and everything and then find out the transfer case is shot. I wanna know EVERYthing before I fix anything at all on this truck. You see where I'm coming from? I'm just clueless about this 4wd and I'd like to know what the problem is and how serious it may or may not be.

ScottyBoy · April 9, 2009

And is there any way to test this Transfer Case Control Module? And any idea where it would be located? And I only paid $10 for the used switch, maybe I'll buy a new one (which I beleive is aftermarket) off ebay for like $40 shipped. But then gain, I'd rather not buy another switch unless it is HIGHLY likely that its the cause of the problem. The previous switch didn't light up at all, but I still heard the solenoid engaging noise when I pressed 4wd Hi and then back to 2wd, but nothing in 4wd Lo.

Original_Prankster · April 10, 2009

Stupid question, but is it in neutral when you try shifting into 4lo?

Draenor · April 10, 2009

And is there any way to test this Transfer Case Control Module? And any idea where it would be located? And I only paid $10 for the used switch, maybe I'll buy a new one (which I beleive is aftermarket) off ebay for like $40 shipped. But then gain, I'd rather not buy another switch unless it is HIGHLY likely that its the cause of the problem. The previous switch didn't light up at all, but I still heard the solenoid engaging noise when I pressed 4wd Hi and then back to 2wd, but nothing in 4wd Lo.

I am not sure on the test procedure. I only have a 2WD. But the TCCM should be located on the drives side kick panel. Check all the connections there. I would also check the connection going to the t-case. There is a possibility that the encoder motor(in the T-case) is either not operating correctly or is not getting a signal from the TCCM. You should check out the blazer forum. Those guys are pretty knowledgable.

Stupid question, but is it in neutral when you try shifting into 4lo?

...Oh yeah, good one. I assumed this was done.

ScottyBoy · April 10, 2009

Stupid question, but is it in neutral when you try shifting into 4lo?

I tried it many times, both with the old switch, and the replacement switch. Tried it in park, drive, and neutral. Same result every time, the light just starts flashing.