Four-wheel drive will not engage?

My service four wheel drive light is on and it’s not working I replaced the transfer case module and it worked for a week and then back to how it was. is there a short that’s blowing that module? all my fuses are good. any information on where to go next would be helpful.

Hello,

I had this truck with this problem. I replaced the control switch and it fixed it. here is how in the diagrams below. Check out the diagrams (below). Please let us know what happens.

I replaced the switch still not working. Could i take old TCM to a part store to get any stored info off of it to get a better idea of what to do next?

The system doesn't work that way, it sounds like the encoder is out. Here is how you replace it. Check out the diagrams (Below). Please let us know what happens.

MY four wheel drive stopped working some time ago. I have a 1999 chevy silverado 2500 LT, 6.0, 4x4. It has the automatic push button 246gm transfer case. Whenever i press the button to engage into 4hi or 4lo the lights will flash a few times and the light goes back to 2hi. I hear noises coming from underneath like something wants to engage but nothing happens. After i try engaging for the 2nd time all lights will go and service 4wd lights comes up in the message center. I replaced the Actuator on the front differential and that didnt do anything, then i tried to replace th transfer case motor but it wouldnt slide in. it was the right part, the numbers matched. There is a shaft that sticks out of transfer after the trans case motor is removed and that is what wont slide into the new tran case motor. Im confused because the new motor comes preset to 2hi, and the light indicator in the cab is saying it is in 2 hi. Im not exactly sure whats wrong here. any help would help tremendously. thank you

sounds like the transfer case is in limbo from the bad shift mnotor that you are trying to install. move the shift rod to make sure its fully in 2wd position then install new motor and you should be all set. its a little tricky finding the right spot for the lever, be patient. let us know how you make out

What should i use to try and rotate the shift rod so i dont ruin it?

a pair of vise grips but be gentle

I finally replaced the encoder motor. When i started up the truck i tried to go and drive but the wouldnt come out of park. I shut it off and turned it back on and then tried again and it did go into gear. i moved into the open and put the truck into neutral. i pushed the 4hi button and all i heard was grinding, i waited a few seconds and it wouldnt stop so i shut off the truck. I started it back up and tried again, and all i got was the 4hi would flash a few times at me and go back into 2 hi. I tried 4lo and i heard a few clicks underneath in went back into 2 hi and then 2 hi flashed at me and service 4wd light came on and the control module went out. i turned the truck back on and the module was saying 4 hi for bout 2 seconds and the service 4wd came back on and the lights went out. i can make that stop by pushing the 2hi after i turn the truck on. I am competely lost.

is it possible you put the encoder motor in wrong. try starting from the beginning. remove the encoder motor and with it plugged in put it in 2wd then make sure the transfer case is in 2wd then reinstall it.

I took off the encoder motor and leftthe cables connected and tried to to reset to 2hi, but it wouldnt reset. I heard it click/whine and thats it. the control module lights blinked and said it went back into 2hi, but the encoder motor didnt. Now when im driving ill get the service 4wd more randomly than before. Not sure what triggers it.

DISCONNECTING THE BATTERY WILL RESET THE TRANSFER CASE CONTROL MODULE. THEN SEE IF IT WILL MOVR INTO 2 WD.

When I shift my truck into 4hi fom 2hi you can feel it engage ,but when you start to drive away you can feel it bind up and almost stop the truck. What is going on? Also when your in 2hi and driving you can feel a vibration at about 40-45 mph.Please help me fix this 4 wheel problem. thank you, Bill

need more info.
Does it have push button 4wd?
Are you doing this on dry pavement or in mud and snow?
Is this driving in a straight line,or are you turning?

[quote:e291c8f549="dennyp"]need more info.
Does it have push button 4wd?
Are you doing this on dry pavement or in mud and snow?
Is this driving in a straight line,or are you turning?[/quote:e291c8f549] Denny, Yes it has a push button 4wd. I was trying on snow and dry pavement. I have tried in a straigh line and while I was turning, it did seem to be worse while turning.

this would be a normal condition for dry pavement or when turning.