Hi, I am having a problem with my 4wd in my 95 S-10 Blazer, the amber lights blink and stay solid amber in both 4 low and 4 hi, and I can hear the transfer case and the actuator working and locking in, but when I'm out on the trails, or in a mud hole, I've been told by multiple people that neither of my front tires are spinning, i would like to figure out any potential problems that would not allow the front end to engage, if anybody could help it would be greatly appreciated, thanks.

 

Sounds like you might have a vac issue.

Take a read through this thread and see what you come up with.

 

if the vac issue is still holding strong look to see if the front drive shaft is spinning. might be your TC

 

I check the front drive shaft, and when it is in either 4 hi or low it does not spin by hand, but has some play, it started sucking the front end down when in 4 low, which it hasnt done before, one thing I have tried different, i was told to try moving in reverse 4 hi/lo about 5 to 8 feet, after doing so, i noticed a difference in how hard it wanted to pull forward, could that possibly be the TC or TC switch going out?

 

If the front driveshaft locks when it's in 4wd, it shouldn't be a transfer case issue. Could be the switch but my money is a vacuum leak somewhere. Any issues with the HVAC at all? Try jacking the front passenger tire off the ground, then with the truck in 4wd try spinning the tire. Shouldn't be able to. If you can, the axle shaft isn't locking and you likely have a problem with the vacuum or possibly actuator.

I'm installing a Bravada shaft as soon as I get a chance so I don't have to rely on vacuum to use 4wd.

 

Thanks, I think I have it narrowed down to a vacuum leak somewhere, The truck is currently sitting on 4 jack stands so i can replace my fuel pump, this was the perfect time to test the tire spinning method, I can spin the passenger tire easily in 4 hi and lo, I know its not the actuator because i can hear it functioning, Now I just have to trace where the leak is at.

 

Ok my problem is a little different. When i try to engage 4low something under the truck makes a loud clunking noise while the orange/yellow light blinks on the 4low button but does not hold steady??? Its a horrible sound and the 4low 4high or the auto 4wheel will not work. I replaced the transfer case and transfer case motor and still doing it. Im clueless and would like some help. Any feed back would be much appreciated.

 

I found out that my problem wasnt as difficult as i thought, I was told to take out the battery with the battery box, the actuator is under there, it may still sound like its engaging, but i had to manually pull the actuater cable in and out and it was able to engage by the button,