I have a 99 s10 blazer and the problem I'm have is when i push the button for 4lo or 4hi the light just blinks i feel it changing on the transfercase but the light keeps blinking then I shift it while the light was still blink the truck did move wasnt sure if it was 4lo it was working before then I got my fuel pump change at the dealers and now my 4x4 wont work any one out could help me out let me please thanks

 

your post is a little hard to understand.
Does it go into 4wd but the light keeps blinking?
You can tell if it's in 4wd when you drive and turn sharp it does a little hopping in the front end.

If it's in 4wd but the light still flashes, the problem is you need a new transfer case shift module.

 

While it's blinking, have you tried to drop it into neutral & then back down 2 drive?

 

I copied the following from s-10 forum. I see a lot of member having problems with their electronic transfer cases not allowing their 4 wheel drive to work.


All this info helps as well that I wrote on another forum:

Well, through everything I have gone through with this electronic 4x4, I figured I would share my knowledge as best as I can. If anyone thinks something should be added, feel free to. This is also from gathered information on other posts.

***HOW TO CHECK WHAT IS WRONG***

You will probably know when your 4x4 has failed when you needed it in the mud pit. Mine, for instance, failed by not doing anything when I hit the 4HI button. However, it would go into 4LO.

To read the codes for the 4x4 with electric shift transfer case, install a jumper wire from terminals "J" and "A" on the ALDL (12 pin connector under the driver's side dash)

The lights on the 4x4 indicator (switch) will flash in a pattern, there are only 4 codes, one flash is code one, 2 flashes is a code 2, and so on...

Code "1" is "RAM standby power" and is considered normal, may be caused by clearing the codes.
Code "2" is "Encoder fault"
Code "3" is "TCCM motor circuit"
Code "4" is "RAM/ROM failure"

If you have the codes 2 or 3 check all the encoder motor connections at the transfer case, if OK it will need a new encoder motor assembly.
If you have code 4, replace the TCCM.

Make sure all connections are good and no corrosion, and then it's either an encoder or TCCM.

***TO FIX THE TCCM***

The TCCM is located behind the glove box, and is accessed from underneath the dash. To remove, the kick panel and black cover come off. Then a 1/4" screw holds the "brains" in the dash. The middle computer is the Truck's brain, the one on the backside is the TCCM, and on the front is the small ABS computer. Simply loosen the 2 10mm nuts on each side, and they will separate.


***WAYS TO FIX THE ENCODER MOTOR PROBLEM.***

This is the most common problem, and was my problem.

Cheap way - To clear the codes and reset the computer, pull the 5 amp TCCM fuse, located at the bottom of the fuse box. Wait at least a half hour, and then replace the fuse. Turn the ignition key to run, wait for the 4x4 lights to blink, and then turn off. Repeat 5 times, and then start the truck.

Decent price way - I just went and bought a rebuilt encoder motor from a company off of Ebay. Their company is www.northernautoparts.com The part cost me around $140 with a 1 year warranty and $38 core refund when I send the old one back.

Expensive way - buy a brand new one from GM for over $300.

***HOW TO INSTALL THE NEW ENCODER MOTOR***

Lucky way - Only thing that needs to be removed is the encoder motor itself. Tools needed are a 10mm hand wrench and a 8mm and 10mm socket wrench. The 10mm socket will work on the upper and lower bolts, while the regular wrench is needed for the middle bolt. (Tight squeeze). The 8mm socket is for the electric plug.
Then, just pull out, and wiggle it out of the truck. Install in reverse order.

Unlucky way - This means the encoder motor did not just wiggle out. Now the front drive shaft will have to be removed at the transfer case. Then, a yolk puller is needed in order to remove the yolk from the transfer case. Once this is done, go to the directions in lucky way.

This is as much knowledge as I have at the moment about the beautiful setup called the electronic pushbutton 4x4. Thank you to all that have helped me, and hopefully this will help others in fixing the future.

-=Glenn=-

I wish to Thank Glenn aka gmshades from s-10forum.com


I followed everything and I finally figured out what was wrong.
Thanks Glenn

 

Check your fuse...sounds simple....it might just be that...I had it do that to me...just the fuse...major relief

 

hi ,thanks 4 the 4x4 info ,,,need 2 know which terminals are the "J" & "A" on the ALDL connector ,,??[8D]

 

For your '99

DTC Displaying
[ol]Turn OFF the ignition for 10seconds.
Connect PIN13 on the data link cable (DLC) to a ground. The DLC is located in the cab under the instrument panel on the driver's side.
Turn ON the ignition, with the engine OFF.
Observe the transfer case shift control switch select buttons for flashing codes. [/ol]


[IMG]local://upfiles/2910/19BCC55EF4F34AB3A2BCE3E400D29158.gif[/IMG]

 

Does the same method work to get codes for the Auto4wd transmission in 2001? If not, how (or can you) do you get the codes from this transmission without a code reader?

Terry

 

The TCCM in the AWD and Auto4wd trucks communicates through the Class II serial bus and can only be accessed with a scanner with Class II communication capabilities. Cheap scan tools will not be able to access this and other systems such as the ABS and airbag control modules among a few others.