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Need help fixing 4wd in 94 S10 pickup I bought


rickyd123
03-10-2025, 09:30 AM
It's a 94 S10, auto transmission, 4.3L vortec v6 engine, push button 4wd.
I'm driving down the road and push the 4Hi button to go into 4wd. Nothing happens. No lights on the switch. No click from the TCCM Nothing. I pull over and put it in neutral and push and hold the 4 hi button. It blinks 5 times there's a click from what I assume is the TCCM and a mechanical gear shifting sound under the pickup. All the lights on the 4wd switch are lit. The 4Hi, 4LO & 2Hi. As soon as I put it into drive the lights go out and I'm not in 4wd. I've done the same procedure going from 2Hi to 4Lo and 4Lo to 2Hi and every combination in between. The exact same thing happens every time. Except when I hold the 2Hi button it only flashes 4 times. It flashes 5 times for 4LO and 4Hi.
HERE is what I've tried:
I checked the actuator. It looks good. No rips or holes. I haven't figured out how to check to see it sucking vacuum. It's under the battery and tray and it needs to be running to pull vacuum.
I unplugged the TCCM and plugged it back in. I replaced the push button switch with a new one. After writing it out it doesn't sound like I've tried much, but I'm out of ideas. I don't know what to try next.

aleekat
03-10-2025, 09:39 AM
When I had issues in my 1995, replaced TCCM.

rickyd123
03-10-2025, 01:19 PM
The TCCM is the computer. Right?

aleekat
03-10-2025, 02:09 PM
Transfer case control module behind glovebox.

rickyd123
03-10-2025, 03:38 PM
ok thanks

rickyd123
03-10-2025, 05:53 PM
I'm going to go to my local you pull wrecking yard tomorrow to get a TCCM. If anyone knows the interchange years for the TCCM with my 94 S10 that would help me if they don't have any 94s.

aleekat
03-10-2025, 06:13 PM
From Rockauto.
OEM Part 15988924
CHEVROLET BLAZER 1995-1997
CHEVROLET S10 PICKUP 1994-1997
GMC JIMMY 1995-1997
GMC SONOMA 1994-1997

rickyd123
03-11-2025, 08:56 AM
Thanks aleekat. I'm taking mine with me, but now I'll know the right places to look.

rickyd123
03-11-2025, 03:58 PM
I went to the wrecking yard and they couldn't give me an interchange list for a tccm. They didn't have any 94 S10s. I looked at ones from the interchange list aleekat posted. The tccm isn't wasn't behind the kick panel on the passenger side.
I watched a Youtube video while I was there. The guy said tccm could be in 3 different places. He was working on a 2001 Chevy something. I forget the model. I also read another forum post from a guy who said he heard his tccm clicking from behind his glove box.
At this point I don't know what else it could be besides the tccm, but finding it on these other years and models may prove pretty tough.

aleekat
03-11-2025, 04:11 PM
Mine was behind the glovebox 1998. Try https://www.car-part.com/

rickyd123
03-14-2025, 09:00 AM
When I get a replacement TCCM from a wrecking yard, do I need to clear its codes or reset it and if I do, how do I do that. I thought I saw I need to do that some where.

aleekat
03-14-2025, 10:46 AM
Mine was just plug & play.

rickyd123
04-02-2025, 02:43 PM
The interchange list that aleekat posted didn't fit my 94 S10. Here's the one I had to use.
1992 - 1994 Chevy S10 1992 - 1994 GMC Jimmy 1992 - 1993 GMC Sonoma.
I got a TCCM off of ebay from a 1992 GMC jimmy for $35 bucks and it fixed my 4wd. Thanks for all the help. I would have never figured it out without it.

aleekat
04-02-2025, 04:23 PM
Thanks for the update. Glad you got it fixed cheap.

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