Alright, so I have a 1993 s10 blazer with the electronic 4-wheel drive. It worked fine a while back and I since then I had to replace the digital dash cluster and ( it did involve disconnecting the control switch from the dash, although I doubt I could of damaged it right?) now its not working.


When I turn on the key the green and orange light both flash for a second but when its running and I push 4H nothing lights up, and I don't hear anything but when the engine is running its not very quiet, so I could be over hearing it.. anyways Winter is approaching and I really want this fixed soon! I did read other posts before making my own but it seems like everybody else at least hears the transfer case trying to engage, and I did check the TCCM fuse and it was fine. and there is no check engine light so I don't think I can get any codes from it. Since the lights don't come turn on (on the control switch), when I push the button I wonder if it is in the switch its self.. I just don't want to dump money in parts until I know for sure what the problem is.

All help is appreciated! thanks

 

I apologize for the double posting but decided to give it an update to better explain my situation.

ok, I did a lot of searching on this forum for some help and did some trouble shooting.. here is what I have, ok when I got the blazer it came with a box of new parts most of them just gaskets and such well it had this weird switch thing too and I found out from my research that it was the transfer case vacuum switch, so I figured I'd go ahead and stick it on there, before that though today, I was playing with my 4x4 during every red light (trying to get it to work and I ended up getting it stuck in 4x4 low.

lol it was a nightmare pulled over, had to disconnect battery for a bit then I finally got it in 2H. some times when I push the button I will hear clicking behind the glove box, sometimes I won't, sometimes I hear transfer case motor, sometimes I don't, later on I cleared the codes "gave me 1 and 2" fixed a hole in my vacuum line checked all vacuum lines... I'm going crazy.

Also I forgot to mention, when it does work, it only works when I put it in neutral. I get no response from it in any gear or even in park, maybe that will help explain something also. when it was working properly it would go into 4H while driving down the road. thats why I was doing it at red lights I would pop it up into neutral while waiting.

Like I said it was working fine a couple weeks back, now its back to nothing again no click behind glove box or transfer case motor.. Any suggestions? thanks again.

 

mine wouldnt go into 4H but would in 4L, lights on switch would blink few times, noise behind glove was there but sounded different than before and no noise at the transfer case. replace the switch with a new one, still didnt help...so ask a dealership mechanic friend i know and he told me before u spend anymore money on parts try unplugging the transfer case module (piggybacked on the ECM) for a minute or two and plug it back up and see if that works. so i did and it fixed mine everything works like it did before, u might try it and see, its free way i looked at it cause that module and transfer case components not cheap!!

 

Thanks for the info, I will try that first thing tomorrow.. one thing that does have me confused is that even after I reset the codes and the TCCM (I both pulled the fuse and unplugged the battery) then cycled the ignition switch (5 times).. but afterwords it will still only work when in neutral.. I don't get it, after you reset every thing, its supposed to work right for a little while at least, right?

 

mine never throwed a code when it acted up, so im not certain on that part of it but do kno that DTC's for emissions side of codes take alot more ignition cycles than 5 times, and thats assuming the code dont keep comin back and disconnecting the battery wont delete code either it will still be stored...simplest way to delete is diagnostics code scanner my opinion. the way it was explained to me on those TCCM, they have been known to freeze up, lock up from a glitch or hiccup for whatever reason like a home computer and unplugging and plugging it back up it will reset or reboot itself, just battery or fuse wont completly take away 100% of the energy from it. when i first heard this and had it not been from somebody that i kno thats been a dealership mechanic, i would not have believe it but i tried it cause like i said before it was free and wouldnt hurt to try it. a few months later i seen this very thing about unplugging that TCCM in a 4wheel drive magazine also....makes me wonder how many people over the years got charged for a new TCCM when all it needed was to be unpluged and reset??

 

You were right! finally I did like you said and unplugged it (cleaned the connections while it was off) and when I plugged it back in she worked like a brand new one, Thank you so much for your help, I was about to replace the encoder motor... saved me a lot of money and work.

I must say, I LOVE THIS FORUM!!

 

Instead of making a new thread I figured I would post in here.

My truck is doing something very similar to what yours was Recon. When I got mine about a month I tried the 4wd and everything worked flawlessly. One night my buddy drove my truck to the gas station and like an idiot pushed the 4wd switch thinking it was the lights. Well I got the truck out of 4LO and never used it again until the other day. I went to put it in 4HI and the light started blinking like normal and I started driving not looking at the light again. Come to find out the light was not illuminated and the truck was never in 4wd.

I messed with it a little yesterday and when I pushed the 4hi button it would blink then go out. Now it wont even blink at all most of the time but I can hear the relay click under the dash. I tried disconnecting the battery last night and pushing the 4hi button and it would blink like normal then go out. I pushed it a few more times and it eventually goes back to not blinking at all again. I have tried it in neutral and it wont go in either 4hi or 4lo. I am going to try unplugging the TCCM tonight and see if that does anything.

To me this sounds similar to your problem. Any other suggestions let me know. Thanks.

 

Glad it worked for ya...that mechanic friend of mine has save me alot money over the years with simple stuff like this, hope it works for u to Longer02!!

 

Well it didn't work for me. I checked the codes by jumping the A and J pin and it gave me a code 1 and 3. Figured resetting the TCCM would do that trick but no such luck. Checking this site... http://www.s10extremist.org/tech_art...ctronic4x4.htm it is pointing towards the encoder motor being bad. I guess I will bite the bullet and try changing that.

Edit: Before I try changing the encoder I have another question. After I reset the TCCM I could push the 4wd drive button and the lights would blink as normal but then go out. After doing this a few times the lights eventually would not come on again until I reset the TCCM again. I hear nothing under the truck and the actuator would not move at all either when the buttons are pressed. I only hear the TCCM click. Will the actuator still try to move and do something even if the encoder is potentially bad? How about if the TCCM is somehow bad? I inspected the actuator and couldn't find anything wrong with it, although it is really nasty and dirty, ha. I also checked some vacuum lines and they seem good as well. Anything else you guys would try before changing out the encoder motor? Should I try a different TCCM if I can find one? Thanks all.

 

There were absolutely no respons in my switch before i came over this thread, and now it works perfectly! Everyone should know about this! THANK YOU!