So I just got this 99 Blazer LT, when I bought it the 4WD worked 2 days later the push buttons were not even lighting up!
I went to my mechanic and he was able to turn the lights on and off with the diagnostic computer thingy they have, however when he tried to engage the 4WD out of 2WD it said "unable to engage." He said just drive it in 2WD for now till I really need 4WD. He said he thinks its the transfer case.
- I was just wondering if anyone had this problem?
- Was it the transfer case or something different?
- simple fix?
- How much $$$?

P.S. I have a 4WD for a reason, i really need it lol! I want to start taking the back roads and hitting some mudd! Whats he talking about "when I really need it"

 

How many buttons do you have? Did the TCCM have any stored codes?

 

4 buttons...., not sure what a TCCM is nor about any codes? sorry

 

If it has an AUTO button, it would be 4-button (Auto4wd, 2HI, 4HI, 4LO)... The direction we go in depends on what system you have. 3-button = 2HI, 4HI, 4LO.

The TCCM is the transfer case control module. It is located behind the passenger side kick panel just ahead of the passenger front door.

 

Sorry i Edited my last message about the number of buttons when i figured out how many buttons there were. It is a 4 button system, i have not checked anything out with the TCCM though, dont want to mess with it when i dont know what im doing.

 

I would start by getting the TCCM scanned using a capable scan tool. A generic one will not work. This is especially true if the 'service 4wd' light is illuminated on the dash. If it is, then the TCCM has stored codes which will point you in the right direction for diagnosing the problem.

If the service 4wd light is not on, then you may want to go straight for the TCCM itself and check the connections for corrosion. Clean as necessary (may require the disassembly of the connector itself).

 

I've had this same problem and it is most likely your 4x4 control module just like swartllk said. Very easy fix. It behind your passenger side kick panel. Just give it alittle tug and it will come wright off, no bolts or screws holding it in. Once you get to it its only 3 bolts to remove it. And one wiring harness. Take you about 5 min to remove. Then you can get one at a local junk yard for between $50-$100. Also watch e-bay. I bought mine for $25.
Also once you get to yours their will be a sticker with the exact part number you will need to get a new one. It might be alittle more money if yours has the auto 4x4. Hope this helps.