1996 Chevy Tahoe 5.7L automatic 4x4 wont go into 4wd high. locks into 4wd low normal, but the light on 4wd high doesn't come on. it reverts back to 2wd. 4 low locks in easy. 4 high doesn't do anything,
Check the bulb in the 4WD switch, that bulb has too work for the system to function properly, if the bulb checks good, then you could have a shift motor range sensor bad, part of the transfer case shift motor assembly.
Thanks so much for your reply, since then, the 4h light will blink, but it will still revert to either 2wd or 4l depending on what I select, but 4h just clicks blinks and goes back to 2wd. I don't have a bunch of money to put in this, I could fix it if I could find out what it is. I could send you a video of what it is doing somehow, don't thing you can post videos on here. thanks for your help, its greatly appreciated...
You could try this: put the transfer case in 2WD then remove the transfer case shift motor and ground it then have someone push the 4WD HIGH button and watch the motor for movement, it should move to match the 4 HI location, then have then push it into the 4 LOW position it should move to that location, now have them put it back to 2WD the motor should reverse direction back to the spot where you started from, this will confirm that the motor is capable of running a full cycle, if it fails and part of the test then replace the motor assembly, if it passes then you need to manually turn the split shaft on the transfer case into the 4 HI position to find out if it will actually go into 4 HI or if it won't engage the gear change internally, you will need to actually check this to make sure the 4WD is engaged, cause if it don't that will cause it to revert back to 2WD, when you select 4WD LOW you bypass that position in the control module so it isn't looking for the 4WD HI position. HTH
I humbly appreciate what you are doing to help me on this matter, I will try it with a friend of mine the first of the week. you seem very knowledgeable about this and what you are saying tends to be the problem. others have yelled actuator, actuator, actuator and I couldn't see that. it worked two weeks ago, went right in 4h, but when it snowed and I needed it this happened, go figure..but I will get back with you after I do what you said Monday or Tuesday, calling for more snow and ice this weekend....COME ON SPRING!!!!. Thank you and have a wonderful weekend...........David
I owned. 96 Tahoe myself and the only 4X4 problem I had with it was the transfer case shift motor, but mine just up and quit working so I knew it was that when I took it off and it didn't run doing the test, I did get it to run after smacking it with a hammer but ad I already had it off I replaced it with an aftermarket unit and never had any more trouble with it, and the guy I sold it too he never had any problems until he took a corner too fast on a slick road and smacked a tree.
Too bad about the tree! ouch.....but what you said just made sense, mine done the same thing, worked great, then just didn't, but it sat for 3 yrs. before I bought it so that's where the ground you spoke about came in, and the motor you mentioned. but I will keep you posted and thanks again....