My son has a 1991 S-10 Blazer with a 4.3 V-6. The 4X4 floor shifter seems to work properly but when shifted, the truck will not go into four wheel drive. The indicator light near the floor shifter shows that the truck is in 4 high all the time but it always stays in two wheel drive.Are there other things for me to check before buying a new transfer case?

 

It could be the transfer case is in 4wd but the front axles are not engaging.
With the truck on the ground, transfer case in 4wd, see if you turn the front driveshaft by hand. If you can't, it's in 4wd in the transfer case bt the front axles are not engaged.

Another way to check..CAREFULLY
If you jack the rear wheels off the ground, run the truck in 4 wd and see if the front drive shaft is turning.
Look from the side of the truck while s 2nd person is in the truck ready to hit the brakes. Careful!
Check it and let us know what you find.

 

this helped me out. good info as well.

https://blazerforum.com/m_52228/tm.htm

 

Yes, that is an excellent post kakn.
I was trying to see if the problem was in the transfer case or the front axle actuator.

 

Put the puppy on 4 jack stands make sure the whole thing is off the ground. Then test. SAFETY FIRST always. Seems like maybe the front axle is not engaging. Also check your front axle some of these actually had MANUAL locking hubs.
You can check the Front shaft with the truck off, just start the truck put it into 4x4 roll backwards about 2 feet then forwards again. Shut down and crawl under. If you can spin the front shaft freely if so then the t-case is not engaging.

Most say that they dont have Jack stands. Well at $20 a pair at Wal-Mart for 3 ton stands. There is no reason not to have a set to be safe.

 

the shift indicator lights on my blazer are messed up. i think most are. my lights flicker on and off when im driving and when i actually have it in 4hi the lights never come on. i personally wouldnt go by the lights but thats me.

one thing that helped me out BIG TIME was the search icon on the top of the page. i popped in some key words like 4x4 not working an 4x4 and what not. it will pull up any posts that have that word or topic. but when in doubt feel free to ask. at one point in time we were all new here. im still new and dont know a damn thing about blazerz lol

by the way....... i noticed this was your first post. welcome to the board. these guys and gals will take care of ya!!

 

Thanks for the advice. My son advises me that the front drive shaft does lock up when the shifter is placed into four wheel drive. I'm now assuming that the problem is probably the actuator on the front axle. Is this correct? I'll look at it a little more once we've dug out of our four foot snow drifts here in southeastern Colorado. This would be an ideal time to have the four wheel drive working. Thanks again.

 

Well you have narrowed it down to three possible solutions:

1. Vacuum Switch (t-case)

2. Vacuum Actuator (under battery box)

3. Cable to front differential (might be rusted, need lubrication [WD-40])

 

Got it fixed. I found a broken vacuum line from the transfer case to the vacuum switch.It's working great now. Thanks to everybody for your help.