I had my dealer look into my service 4x4 light. They spent about two hours troubleshooting the issue and state it is my transfer case module.

The switch does not light up the 2wd light all the time, I have to push it or move the switch for it to light up most times. If I go to 4 high or 4 low the light lights up although I do not believe I am actually in 4x4 becauseI can put my rear wheels in a snow bank and they will spin while the fronts remain still. Yet when I go into auto 4x4 then the fronts will kick in.

Just wondering what you guys think the problem is before I spend $360 for a new module at gmpartsdirect.

Thanks.

 

Not knowing a lot about the system, but going by the symptoms, I would think the dealer is right. I would think you could find one a whole lot cheaper somewhere else though. If you think it could be the switch, you can pick them up somewhat cheaply and see if it solves the problem. If not, just return it for a refund (I saw one without the auto at oreily's for like $40)

 

Really could use some suggestions here. I am not that familiar with the mechanics of a blazer and the dealer wants $550 to replace the TCCM!!

So this is what is happening. They state they were not even getting a good connection from the module. I can not go into any 4x4 except auto. The lights on the switch are only working some of the time. They go on an off when trying to switch. I no longer have my service 4x4 light on.

When I hit 4 high or 4 low you can heare the TCCM click and it sounds like the 4x4 engages but it is not as the front wheels still are not spinning. When trying 4 Low and I go into D it is like it is in 4x4 but as soon as i hit drive it pops out and there is no 4x4.

Any ideas on what and where to check?

The encoder motor was repalced with a used one about 8,000 miles ago.

 

Do you have Auto4wd (I suspect you do from your other thread)? If so, what codes did the dealer pull from the diagnostic? What did they tell you needed to happen (specifically).

As I said in your other post, "You have 4 basic components of the 4wd control system. Switch on the dash, TCCM, Transfer case encoder motor, and the front axle engagement actuator".

 

I hope everything is figured out now. I bought a used updated module from Ebay and now I can shift into 4x4. Although the lights are flakey on my switch. Most of the time they are not on at all. If I push it or tap it the light may come on. So I have ordered a new switch. I should know soon. I will let you know. Thanks.

I apologize for the double post, I forgot that I had posted it on this forum already. I see you combined the threads, thank you.