I just bought a 2002 Blazer which I plan to use for fishing, and will be driving a lot on the sand. I figured I would use 4Hi, but when I press this button nothing happens.

I read the manual, tried putting the car in neutral and then doing it again. This time the 4Hi and 4Lo lights come on - they stay solid for a couple seconds, then when I press either the 4Hi or 4Lo they flash and then both lights turn off.

I have no idea what I am currently in, because there is no light next to anything - I assume I am in 2Lo(?). Also I do not have any message to service 4WD.

Any ideas on what is wrong? From what I read online it seems like this is the transfer case control module, but I honestly have no idea. Please let me know your thoughts. Thanks!

 

Al right...another 2002 owner....!!

First off, there is no 2LO, only 2HI and then 4HI and 4LO.

Several things to do:
1) Check or better yet replace all the vacuum lines under the hood, especially the ones in the left upper corner. Just purchase about 10' or so of vacuum line at the local auto parts store and replace one line at a time....starting at the engine/vacuum source.

There is a vacuum line from a switch in the middle of the firewall that runs under the battery tray to the front differential vacuum actuator. Be sure to replace this one.

2) Pull the battery out and the battery tray and check the vacuum actuator diaphragm, make sure it is not leaking. Also pull on the cable with some pliers and make sure it moves and not stuck.

3) Remove the 4WD switch panel from the dash and disconnect the electrical connector. CAREFULLY separate the two halves of the assembly to access the circuit board. Reflow every solder joint, especially on the connector pins. Use no more than a 25 Watt soldering iron....no large soldering guns!!! Re-assemble switch halves and put back into dash.

4) Pull off the right side bottom trim panel to access the TCCM module. Clean the contacts in the two connectors.


Once all of this is done, now try the 4WD, or do one at a time...up to you.

Not a "sure thing" that one of the above will get you 4WD, but if none of the above works, then it will be time to remove the electric motor on the transfer case or replace the TCCM. Good chance it is one of the "fixes" in my list above.

Let us know what happens.

Good luck.

 

Lanny, thanks for the detailed response. I am not very mechanically inclined....at all, so 3 is definitely out of the question.

I found a used TCCM that is plug-n-play, and works for $25 on eBay, was thinking that may be the easiest first check. What do you think? Thanks again!

 

The TCCM is actually pretty reliable. I would check / replace all the vacuum lines first. I know I had to replace the vacuum switch on the firewall on my '02. Very easy to do: one electrical connector, two vacuum hoses (do not mix them up), switch just slides into its holder. Got the replacement at RockAuto.

But before replacing any parts, need to do some diagnostics to determine what is wrong first.

Where abouts are you located at? There might be a Forum member nearby to help out.

 

I'm in NY you aren't in Long Island by chance are you

 

Sorry but no, not even close. I am in Arizona. Does it count that my '02 Blazer came from Long Island...LOL...

I still suggest first thing to do is to simply check vacuum hoses/lines. If you need pictures, send me an email to deanvette@comcast.net and I can take some pictures and send to you.

 

Thank you! I sent you an email