1997 GMC 1500 4WD won't engage and just blinks

[b454rat]

Can’t believe no one mentioned the t-case motor. I’ve had couple of these pieces of **** systems and every time it’s the motor. Last one I did sounded similar to urs. Wouldn’t engage, but on jack stands the front would lock in, couldnt turn the driveshaft, but on the ground and no 4wd. Wouldn’t go in low either. Replaced t-case motor, worked great. 4high, 4 low, worked as it should. The motor might shift it in to 4wd, but gears arent engaging all the way, why it clunks n grinds.

 

[Burb Burb Burb]

How would I go about checking the actual 4x4 switch on the dash to see if it's good or not? From what I've been reading these can go bad and cause the problem as well. Thanks.

I had a similar issue on my 99 burb: intermittent lights on the 4wd switch. It would shift great sometimes, and be dead at other times. Turned out that the leads on the back of the 4wd switch were corroded. Cleaned 'em up w sandpaper, then a touch of dielectric grease. Now 4wd switch lights up like it should, and switches in and out of 4wd on command.

Giddy up!

 

[Dannothemanno]

I'm just hoping someone has an answer but I'm also having issues with my 4x4 it seems that one of the wires on the connector that goes to the acuator isn't getting power and it's the wire that looks green or blue and I replaced the tcase switch could it be my encoder motor?

 

[Rahooo]

Can’t believe no one mentioned the t-case motor. I’ve had couple of these pieces of **** systems and every time it’s the motor. Last one I did sounded similar to urs. Wouldn’t engage, but on jack stands the front would lock in, couldnt turn the driveshaft, but on the ground and no 4wd. Wouldn’t go in low either. Replaced t-case motor, worked great. 4high, 4 low, worked as it should. The motor might shift it in to 4wd, but gears arent engaging all the way, why it clunks n grinds.

Can you provide a part number? I cannot seem to find it