Hello Everyone -

I have a 99 Blazer-Trailblazer 4x4 4.3 vortec- electronic 4 wheel drive. My question is i hit the 4x4 switch and it blinks then goes right back in to 2 wheel drive. Whats the deal? PLEASE HELP!!!!

 

Well I'm not going to be much help because I have the same problem. If you search the forums you will
see all kinds of info. One was to change the vacum lines, which I did but didn't change anything. My problem is the same as yours, I hit 4hi button and the light come's on and stays on along with the 2hi light and nothing happens, then I hit the 2hi button again and then both 4hi and 4lw lights flash once and go out then 2hi comes back on and that's it. After a couple of times of this then neather of the 4wd buttons work. Need to unhook the battery to reset them. Go figure.
Last word I got from a mechanic around here was the dash switches are bad, replace them. I guess that's my next try.
This doesn't help much but it might help with respone's from some. there are a couple of guys who seam to know the 4x4 systems really good on this forum.

Good Luck

 

is your tcase fuse blown?? would start there

 

Since this is a "TrailBlazer" option Blazer do you have the AUTO button??? as another 4x4 button... this will have a different t-case than a standard 4x4 blazer LS or LT option...

 

Does the SERVICE indicator (4WD/AWD) Lamp light up?
Usually when the light flashes then returns to the original button, that means the transfer case was unable to complete the shift.
The first thing to do is check all the fuses under the dash and the fuses under the hood.

 

Yes my service 4wd light is on. I checked all the vacuum lines everything is ok. And about the seperate transfer cases my all wheel drive comes on ( at least i think) but the the 4 wheel drive does not.

Thanks

 

I would suggest that you get the code read. There a about 17 possible codes, so knowing which code should help to locate the problem circuit.

 

With the "AUTO" 4x4 tranfer case instead of direct connect to the front differential it uses a planetary gear/clutch setup similar to a positive traction unit in the differential. If this fails then you would not be able to get the transfer case into 4x4. Also check to see if the Encoder Motor is working, it is located by the front output shaft, it has an electrical connector on it. One easy way to check if your AWD/4X4 is engaged is to attempt to make a tight turn on wet/dry pavement, there should be some resistance in the steering wheel if the front differential is engaged.

 

Under the battery plate is the 4x4 solenoid. Check the vaccum lines then the accuator cable.Mine was stuck and with some wd 40 and
using a plier topull and push the cable a few times fixed the problem. Hope this helps.

 

Thanks for all the help guys. Will try and mess with the actuator tomarrow.