4x4 encoder / tccm problems 1999 blazer

[bradhaight]

Okay, new thread.1999 blazer . I have four wheel drive 4 button on the dash.. I have four wheel drive in 4 auto, I will switch to 4 hi and loose the front axle. I will switch to 2 hi, will get four wheel drive four about 2 seconds, in the switching mode.. My front actuator is properly working.. and cable which I had to replace last year... I have a locking front wheel axle when I am in 4hi 4 auto and 4 lo.... the question is from the transfer case control module tccm on the right passeger kick panel, I get a 2 clicks when switching from 4hi to 2 hi, and during this last click, is when I loose the front axle... Also my encoder motor seems to go in one directions then turn back out.. I will keep you all posted on the final outcome, was it the encoder motor, or the transfer case control module, or dash switc??? In the mean time if any body want to help throw in the 2 cents, I am open.. I just puchased a encoder motor off ebay and hope to install it next week.. if that does'nt work I will have a encoder motor for sale on ebay... then I will be in the need of a 4 button tccm..


thanks for the past expertise, still not working corectly in ohio


brad

[ricksza]

If you have access to a scanner, chech the output of the switch. It works on resistance, and some have been known to send the wrong signal to the encoder motor. I've seen 2 wheel low on the scanner, didn't even know that it was an option.

[Heli]

I'm interested in this thread. I still have a problem with my 4 wheel low. it's either the encoder motor or the TCCM not sure how to check either one. What scanner are you refering to?

Regards,
Heli

[bradhaight]

Originally Posted by Heli

I'm interested in this thread. I still have a problem with my 4 wheel low. it's either the encoder motor or the TCCM not sure how to check either one. What scanner are you refering to?

Regards,
Heli

Okay, I broke down, and had a diagnose.. WoW. Service advisor, took me to the mechanic, and said, you got major problems inside the transfer case. I asked how he came to this conclusion.. Well I just got stuck in the back lot in 4 hi.. I said push the 4 auto and you would not of gotten stuck. He goes what!- 4hi is 4 auto.. I said lets go back in the back lot, again, and he shifts to 4 auto, and as stated front axle worked fine.. He states in 5 years of working on 4x4 blazers, he never seen this senario?? He starts to dig deep, and pulls the codes from the gm obdII scanner.. and yes he comes to conclusion, that it is the encoder motor after all... Now I puchased one off ebay, and not yet proven the bad encoder motor theory.. I will say this, there is a 6 prong sensing unit on the encoder motor which I can't pull any resistance off of in numerous position.. It is sealed.. and I guaranteed this is the problem.. looks like a 30.00 part, but not sold separately and has to be purchased for 500.. plus.. GM ??? another part failure, connected to a more expensive part.. I purchased my for 39.00 plus shipping on ebay.. but there is a guy who sells recondition ones on ebay store for 219.00

I will keep all update on the encoder motor.

[ricksza]

Originally Posted by Heli

I'm interested in this thread. I still have a problem with my 4 wheel low. it's either the encoder motor or the TCCM not sure how to check either one. What scanner are you refering to?

Regards,
Heli

The scanner that is use is from GM called a Tech 2 made by Vetronix. Various manufacturers have different models that basiclly will read that same data.
From 1999 and newer, if you have an automatic style transfer case, you can tap into the data stream through the DLC connector under the dash near the parking brake pedal. With this data, you can see different parameters such as shift request. This would be the signal from the switch to the TCCM (transfer case control module).
There is a common problem with switches giving the wrong request to the tccm, but the only way to see this is with the scanner.
If you need any additional info, let me know. I'll get it to you.

[bradhaight]

Originally Posted by ricksza

The scanner that is use is from GM called a Tech 2 made by Vetronix. Various manufacturers have different models that basiclly will read that same data.
From 1999 and newer, if you have an automatic style transfer case, you can tap into the data stream through the DLC connector under the dash near the parking brake pedal. With this data, you can see different parameters such as shift request. This would be the signal from the switch to the TCCM (transfer case control module).
There is a common problem with switches giving the wrong request to the tccm, but the only way to see this is with the scanner.
If you need any additional info, let me know. I'll get it to you.

Okay/ just put in the encoder motor/ and wow/ I now have 4hi 4lo and very happy.. total cost 64.00 for diagnostic check from gm + 54.00 for a used encoder motor from easton auto salvage 610-258-2925.. great service.. purchased on ebay .. they have a bunch of blazer in the yard.. good people.. hope this help other

[jleonard]

I own a 1999 Blazer in which all the push button 4x4 lights light up and the service 4x4 light comes on. When this happens it loses power and wont shift. If you unplug the push buttons, it should default to 4hi. (and not act up) I did this and mine didn't default to 4hi and acted the same. This is surely a sign of a faulty tccm. I hope this helps.

Jordan.

[old_master]

Originally Posted by jleonard

I own a 1999 Blazer in which all the push button 4x4 lights light up and the service 4x4 light comes on. When this happens it loses power and wont shift. If you unplug the push buttons, it should default to 4hi. (and not act up) I did this and mine didn't default to 4hi and acted the same. This is surely a sign of a faulty tccm. I hope this helps.

Jordan.

This thread is almost 4 years old, please post a new thread in the "Blazer Problem Diagnosis" section. You can copy and paste your question into a new thread in that forum. Thanks