I have a 94 4x4 S10 Blazer with the Vortec 4.3, It has 187,000. I bought it a few months ago for $500.00. The dealership thought the oil pump was bad, it wasn't, guy was just a moron and the oil was so thick it didn't pump through. So to make a story short, It runs perfect now driving everywhere for the last month and a half with no oil burn. I went to change the plugs, wires and cap yesterday and found a vacuum line unplugged right near the cap, I thought I yanked at some point. NOPE!, it turns out when its plugged in the 4x4 kicks in and won't shut off with the button at all but the 4lo light turns off and on(although 4wd stays on when vac is plugged in), so I would like that vacuum line plugged in to make my vents and whatever else it may do work. So any help would be great. Can't figure out what would be wrong? I wanna replace whatever it is.

PS> I have a 1989 S10 Jimmy, I think the transfer case and everything is the same? But it does have a manual shifter instead of electric push. Is it different in ways? or the transfer case and all is the same? I will take whatever from it if this means my 94 will work proper.

Please HELP!
Thanks
Conrad

 

It is quite possible that the vacuum switch on the transfer case has failed.

When you put it into 4HI, can you spin the front driveshaft? When in 4LO, do you feel the gear ratio change? When in 2HI, can you spin the front driveshaft?

 

My '89 had that 4wd problem when I first bought it, the vac line was unplugged at the dist and the diagram under the battery, turns out it was nothing more than a bad transfer case switch, I'm not for sure, but I think your switch is still on the transfer case