1995 Blazer (Midsize)

TPLANE37

MEMBER
1995 CHEVROLET BLAZER

1995 S-10 Blazer, 4.3L H.O, Automatic, 4x4, 250,000 miles. I am having yet another issue with my 4wd not functioning properly. Push button 4wd on the dash.

4 LO engages, set in "N" push 4 LO, both 4 HI and 4 LO lights flash 3 times, you here the case lock in, and you are in 4 LO. But both lights stay on steady. Push 4 HI. Nothing, at any time (from 2 to 4 HI, nor from 4 LO to 4 HI). It doesn't matter if you are moving or not, and it doesn't matter what gear the tranny is in. From 4 LO, it will go back to 2wd as long as you are stopped and in Neutral. Any other ideas (beside buying a new truck?). This truck is still running strong and has been properly maintained all it's life, recently drove from Southern California to Central Illinois stopping only for fuel (2200 miles) and everything else is great, but I need 4 HI for the Illinois winters since I am back.

Xfr case motor has been replaced, no play in linkage, Vacuum pod replaced and vacuum lines rerouted as per TSB's in "Mitchell OnDemand" and "AllData." I am thinking the switch on the dash but would like a second opinion. Is there a way to remove the electrical BS and install manual linkage instead of the push button? I have everything out of an '89 4x4 Jimmy, but I am unsure of the internals matching up as far as the t-case to tranny. (And yes, I realize I would have to cut a hole in the floorboard. That's just minor mods. Or is it possible to put a 1/2 ton 80's model t-case in? Thanks.

5 Replies

CHEVY22

MECHANIC
1,375 POSTS

As long as you know the encoder is ok we will rule that out, and you stated you replaced the vacuum solenoid so I will leave that alone, do the lights cycle when they key is turned and if and when they do you should see a red light very quickly on the switch, also listen to your right when turning key to run you should hear a relay click in the tccm which is behind the right kick panel

lemme know
jim

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Friday, October 12th, 2007 AT 4:49 PM

TPLANE37

MEMBER
3 POSTS

KOEO, 4 LO and 4 HI lights come on (2 HI light has been burnt out for years now, prior to 90% of all 4wd issues), Relay completes it's test (it clicks). After the relay clicks, the lights on the 4wd switch go out. Near the same time as the rest of the dash lights. I did not see a brief red light on the switch, but if it happens under the 2wd button, it may use the same light, I am not sure.

Also, when you pres 4 LO, you hear a click just before the motor engages, this is not the case when you press 4 HI. You here absolutely nothing, you feel nothing, and you see nothing when you attempt to put it in 4 HI. Thought I would add this, because it might help since you aren't sitting here to play with the buttons. Another note, my sister used to own this truck, when she did, a friend of her's put an aftermarket stereo in, and he screwed up a bunch of things including the Hazard switch, I replaced that, but that was a different issue. After he put the stereo in, the 4wd would not work at all. Then, when I had to put a heater core in about 6 months ago, I unplugged everything on the dash bezel to get it out of the way, when I put it all back together, the 4wd started working, including 4HI. But it was the same senario, 4HI would engage 4HI, but both 4wd lights were on same as 4LO. This is why I am leaning towards the switch because I believe the guy pulled the wrong way on the switch when he put the stereo in. Just an FYI.

Thanks again.

Was this

answer

helpful?

Yes

No

Saturday, October 13th, 2007 AT 12:12 PM

CHEVY22

MECHANIC
1,375 POSTS

Ok heres what im thinking, the switch is bad any way, grab one from the dealer and replace it, the switch is 20 bucks or so, if this doesnt solve your problem we are probably looking at the tccm if the truck is obd2 it will be in the right kick panel if its obd1 it will we mounted on the heater behind the center of the dash right below the stereo almost, where work was done, so in my opinion do the switch and lets see what happens like I said its bad anyway, also were having site problems and I dont get a notification of replies to posts so if you dont hear from me use the pm to let me know you posted but lets try and keep it here so other people with the same problem can see it

thanks

jim

Was this

answer

helpful?

Yes

No

Saturday, October 13th, 2007 AT 12:35 PM

TPLANE37

MEMBER
3 POSTS

I will be picking that switch up today, I won't have it put in until tomorrow. I'll keep you updated. Also, this is an OBD I system, OBD II stared on these in 1997.

Was this

answer

helpful?

Yes

No

Saturday, October 13th, 2007 AT 12:58 PM

CHEVY22