Relist: Incomplete answer.[email protected]
Original question to justanswer:
I have a 1998 Chevy Blazer automatic with electronic transfer case switches. I was in a three foot snow drift and had to use 4LO to get out. With the vehicle in neutral and stopped, I pressed the 4LO switch. Although I was able to get into 4LO, both the 4HI and 4LO indicators blinked for a few seconds and stayed lit. Then I could not transfer from 4LO to 4HI. Per instructions in the Chevy manual, I was able to get into 4HI by pressing the 4HI switch in neutral and quickly shifting into park while the 4HI and 4LO indicators were both blinking. The Chevy Owners Manual says, if your transfer case does not shift into 4HI, your transmission indicator switch may require adjustment. After the transfer was made to 4HI, both the 4HI and 4LO indicators stayed lit. I then shifted into drive and was good to go until I switched into 2HI on the fly. The 4HI and 4LO indicators blinked for a few seconds then the 2HI indicator lit up. Then when I tried to transfer into 4HI from 2HI, I depressed the 4HI switch and both the 4HI and 4LO indicators blinked for a few seconds, but no transfer was made to 4HI. I was not able to get out of 2HI and the 2HI indicator stayed lit. Do you know what adjustment Chevy is talking about? What else could be wrong? Thanks for your help.
Sun, Mar 21, 2010 7:34 AM EST Original answer:
Hello and welcome. the most common reason for this problem is a bad encoder sensor inside the encoder motor. try this and let me know if this takes care of the problem. disconnect the battery for a few minutes. reconnect the battery, start the truck up, place the transmission in neutral, switch the 4 wd from 2 hi to 4 lo and back to 2 hi. do this several times. this sometimes will clean the encoder sensor. [email protected]
Thanks for your quick response. Unfortunately, disconnecting the battery did not help, but playing around with the switches provided new results. I can not get into 4HI no matter what combinations I use, i.e., which switches are depressed or whether I am in neutral or park. However, if I am in neutral and press 4LO, I can transfer to 4LO if I quickly shift into park while both the 4HI and 4LO indicators are blinking. To get back into 2HI, I am stopped and in neutral. I depress 2HI, the 4HI and 4LO indicators blink, then the transfer to 2HI is made and the 2HI indicator lights up. Question 1: Does this still sound like an encoder sensor problem? Question 2: Can I buy the encoder sensor by itself? Question 3: What about a salvage yard encoder? Question 4: Could my problem simply be a faulty dashboard electronic transfer case switch unit? Question 5: So I can talk intelligently to my mechanic, would you please briefly explain the functions of the TCCM, encoder motor and actuator? Question 6: Lastly, before I replace anything and start throwing money after parts, should I get a Tech 2 diagnosis?
From goodwrench9124 Followup answer
Mon, Mar 22, 2010 6:52 PM EST
Answer to question 1: very possible it is a encoder problem, New answer: but there is one other thing that happens with these trucks. over on the passenger side, behind the right kick panel is the control module for the transfer case. remove the kick panel and unplug the connectors for the transfer case module. look inside of the connectors and see if there is a powerdly green colored substance on the connector terminals. sometimes the connectors draw moisture and cause a bad connection at the module. here is a picture
Note: My dissatisfaction with goodwrench9124 answers is as follows: I already researched the TCCM solution myself and found the same information. Questions 2 through 6 were not answered at all.