99 Blazer stuck in 4low

[DSG AUDI]

I have a 1999 4wd blazer with a 4 WD problem. It has the 4button transfer case. It shifted itself into 4 low and won't come out. When you press the buttons nothing happens, it doesn't even blink like it is attempting to change. I tried resetting the computer and after doing this the 4L button will blink but not allow you select any other setting. Soon as you start moving the button stops blinking and it stays in 4L. It started having problems about a year ago and was fine after restting the TCCM and replacing the switch. Does this sound like a bad TCCM? I pulled the kick panel and found the part # 15154323 on it. I have searched but found nothing on this TCCM. It is also not on the GM Parts Direct website. Thanks

[MT-2500]

4 shift buttons with no auto mode button .
You can ground pin 13 on diagnostic connector and pull codes.
key off ground pin and key on watch for and count blinks on shift buttons.
Post back code no.
Have you checked all fuses for 12 volt power on both sides with key on?

Also check how to section and run a search on it.
http://www.automotiveforums.com/vbul...d.php?t=572914

[DSG AUDI]

Originally Posted by MT-2500

4 shift buttons with no auto mode button .
You can ground pin 13 on diagnostic connector and pull codes.
key off ground pin and key on watch for and count blinks on shift buttons.
Post back code no.
Have you checked all fuses for 12 volt power on both sides with key on?

Also check how to section and run a search on it.
http://www.automotiveforums.com/vbul...d.php?t=572914

Yes fuses are good. I tried to run that check about a year ago when I was having problems and there is no wire in the OBD2 port in that position. I replaced the switch so I thinnk that all that is left is the TCCM. Like I said the lights on the switch don't even blink when pushed only the 4L will blink after the TCCM is reset. I found out that 12577412 replaced the 15154323

[MT-2500]

There is more than that to them.
It needs proper testing not throwing parts at it.
Which transfer case do you have 233 or a 236.
What does the ID tag on the back of it say?
If your shift buttons have the auto mode button.
You need a scanner to get codes.

[DSG AUDI]

Originally Posted by MT-2500

There is more than that to them.
It needs proper testing not throwing parts at it.
Which transfer case do you have 233 or a 236.
What does the ID tag on the back of it say?
If your shift buttons have the auto mode button.
You need a scanner to get codes.

It has an Auto button. Will a universal OBD2 scanner pull the codes? The "Service 4wd soon" light has come on before.

[MT-2500]

Then you have a 236 transfer case.
That is the reason the diagnostic connector does not have a pin 13.

But no a OBD11 scanner or code reader will not pull codes.
You need a engine/transmission/transfer case scanner to test or pull codes.
The high end high dollar jobs. 2-5K range scanners.
GM Tech2 or a snapon scanner with the right or 3 in 1 cartiage will get the job done.
Beside pulling the codes they have a lot of function and shift test to test and check it out.
Your best bet is to fnd a good repair shop that has the scanner and have them test it for you.
If you get any codes post back codes.
Good luck MT

[DSG AUDI]

Well I took a chance and bought the TCCM and it fixed the problem. Got a pretty good deal on it fom the dealer. Thanks for the help.

[MT-2500]

Thanks for posting back how it went.
Glad you found the problem and got it fixed.
And 10-4 on the dealer good deal.
MT