I just bought a 94 Jimmy yesterday. My boyfriend has a 94 blazer and I loved it so much that I wanted one for myself. It's currently in primer with 157k on it. I plan on having it painted. There are a bunch of small things wrong with it that I plan on fixing like the passenger window motor, but most of the problems are very small and not a big deal.
The one thing that is driving me nuts though is the 4 wheel drive. I've never seen a problem quite like this so I would really appreciate some help with this issue. The 4 hi won't engage. It just blinks. I know that this is a common thing but the weird part is that the 4 lo does engage most of the time. The problem with this though is that sometimes it engages properly and the light stays on, but sometimes when pressing the 4 lo button both the 4 lo and 4 hi lights are on simultaneously. Also, after finding this out today, I switched it back into 2 wheel and when I went to drive it, it was clearly still in 4lo even though the light wasn't on. I engaged it again and disengaged and that fixed the problem.
What would cause the 4 hi to not want to engage even though the 4 lo will? Also, what does it mean if both of these lights are on at the same time? My boyfriends blazer has the exact same setup and I know his does not do this.
Thanks for your help!

Here's some pictures, and yes, I promise it's a Jimmy. Whoever owned it before must have wanted a blazer pretty bad because they changed the grill and the rims. It was originally blue, so I'm thinking about painting it a dark blue.

 

I had this same problem with my 94 jimmy and it was the solenoid on the transfer case, think it cost almost 300 bucks.It makes a quik mechanical engagueing sound when i lock in and out ive noticed now with it working right.
I am not a mechanic i'll let you know, but this is the same problem i had, gl and cg's on your new jimmy.

 

Thanks for the good wishes. I'm really bummed out about this whole issue. Thanks for your insight. Does anyone else have any ideas or agreements with the solenoid diagnosis?

 

I'd check the easy stuff first - check all your vacuum lines and the vacuum actuator under the battery tray. That's a lot cheaper

 

Will do. I'll let you guys know what I find out. Thanks.

 

Is it push button 4wd? I had an issue where my 4wd was staying engaged, not engaging, and trying to switch on it's own. I pulled the push button control and cleaned the contacts under the buttons and it has been great.

 

I'll definitely try that. How did you get the button off and what did you clean them with?

 

Sounds like the encoder motor is going bad.

 

Sorry for being a noob but could you explain what an encoder motor is and how to go about fixing it/getting a new one?

 

a girl that knows something about trucks.
i'm impressed.