2001 Chevy Blazer..3 button system.


Here's a new one, how often does this happen? So, i noticed there are about 1billion threads about 4x4 not engaging, mine wont get out of 4whi. Wont go to 2wd or 4lo. I can hear the clicking on the passenger side making it "try" to disengage, but its just stuck in 4hi. 2wd button just blinks, then goes back to 4wdhi soild light. Now, i read a few thread's about a vacuum lines and pumps, however, i always thought once the truck is turned off, it disengages 4wd? (At least that's what happens in my tahoe, but that has a heat acting actuator, im assuming these are different?) |

Seeing that where in winter, if i can't find the problem, it doesn't concern me yet, b/c i doubt there's a day from hear forward that i wont be using 4wd, although id rather not damage the Xcase on the highway when not needed.


Anyone stumble across this issue? Or im i going to have to follow the same procedure that if its not "engaging" start "here"

 

Mine is doing the exact same thing. I had one of my mechanics look at it and mine turned out to be the TCCM plug. There are 4 components basically - the actuator, the actuator motor, the TCCM and the shift selector buttons.
The actuator can be taken off and simply moved in and out by hand, if its not stuck, its working. The actuator motor can be taken off, run 12 volts to it and the motor turns one way, reverse the leads and the motor turns the other way, so if it is turning then the actuator motor works.
The shift buttons are probably working, the lights are going and they are making the TCCM click.
Check the TCCM and plug going into it and make sure its not corroded like mine, that is the problem with my truck, my plug is severely corroded and I am currently looking for one.

 

another issue can be a Bad vaccum switch from the transfer case, broken vaccum hose, bad vaccum actuator.

 

unplug the TCCM, it should bring the car back into 2wd.

unplug the box and start the car, it should be in 2wd. turn the car off and plug the box back in. now start the car. if it goes or tries to engange into 4wd on its own after you reattach TCCM it is either the dash switch or the TCCM itself that's messed up.

mine had same problem. i had to replace dash switch and TCCM.

 

I'm guessing that if it hasn't resolved itself by this point, my experience won't be very useful, but...as dumb as this sounds....

I had a '96 Blazer with the 3-button 4WD that did the same thing, mostly. I heard the actuator working, but the light would just flash and then come back on steady for the drive range that the transfer case was stuck in. First it got stuck in 4-Lo (in the parking lot at work, conveniently enough). Since I could hear the actuator working, I decided to keep pushing buttons until the actuator either burned out or finally got the transfer case to go into the right gear. After 20 minutes of poking between the 3 different drive ranges (2wd, 4hi, 4lo), I got it to go into 4-Hi. It took another minute of pushing the buttons in a random order, but it finally went back into 2WD. It seemed to just be a little bit jammed. I only used the 4WD one more time after that, before I sold that Blazer; and it worked fine that time...in all ranges.

So, if you haven't tried that yet, it might be worth a shot. Dumb as it sounds.

 

I did this, at the point prior to trying this method, TCCM was clicking, and switch was working. I unplugged the TCCM..(ign off obv.), started car, put in D and R. Put back in park. Plug TCCM in again. (ign off) Then, turned car back on....Switch still went into 4WD, tried pressing 2wd, blinked..went back into 4wd. I repeated the step, now the Buttons do not turn on, and im not sure if the TCCM is working or not b/c its not clicking.


Im gonna have a bon fire with this truck i think.


**..im gonna chalk it up as a bad TCCM. Judging by the post, something more then likely is not estuck, or not working properly under the vehicle...but im going to assuming it being an electrical issue, even now seeing that the TCCM is not working. Just ordered a used one with a 60 day warranty.


***..I just noticed a crap ton of corroded wires..and a broken one..the plot thickens once again...need a wire harness clip..now i gotta look for that...
Thank you all for your advice and help, it was greatly appreciated.

 

UPDATE: Well, i just replaced the harness pig tale, found an EXCELLENT condition one at the junk yard...cost me a whopping 4.75 cents, and 10mins worth of searching threw the 3feet of snow..tell ya what tho, out of all the S10 bodys there, there where NOT many harness's left, i was rather lucky.

So, its hooked up, and still not sticking, im gonna look at the actuator, my TCCM still hasn't come in yet, but im still thinking its the module for some reason


UPDATE DUCE: So, i removed the battery, to get to the actuator, noticed a fuse block on the inner fender with a small 10amp fuse, and big 30amp fuse and a relay?...The big fuse is blown..(30amp)....now by ANNNNNNNNY chance does this fuse block have anything to do with the 4wheel drive b/c i read nothing about it.

 

Im down to the X-case actuator,..i had to go the "shot gun" way here, nothing was in my computer for the 4wd, more then likely because it was "on" and just wouldn't turn "off". Im picking up a new one tomorrow. I pulled it out, i tried to jump the hot/ground see if i could get any movement, but i got nothing...(im not even sure what the correct way is to jump the unit). I hope this fixes the 4wd.....or im setting it on fire....

 

Can we change trucks, can't get mine into 4 wheel drive. Just bought a 2000 ZR2 yesterday and the 4 wheel drive doesn't work in hi or lo... buttons light up and can hear relay clicking. I've heard there are vacuum lines and actuator on transfer case. Where is the TCCM located? Any suggestions would be helpful as I am just learning this vehicle

 

Those fuses and the relay are for the AIR pump. Nothing to do with the 4wd system. If the 30A fuse is blown, it is likely because the pump sucked up water and then corroded or froze.

If your encoder motor didn't move when you applied power to it, the motor is likely fried or the gears are bound up. Replacement should allow the transfer case to work.

bkn1960, the tccm is located behind the passenger side kick panel.