Blazer shifting into 4WD Low by itself

[chevelle]

My 2001 Blazer shifts into 4WD Low all by itself. The dealer has not been able to re-create the problem and has advised me to tow it in when it happens again. Has anyone heard of this before? What could possibly be the problem? The switch itself? What is the cure?

[somoney7]

Hi Chevelle,

I had the same problem about a month ago. The dealer ended up replacing the 4WD module. In the meantime to make it driveable, once you shift it into 2WD remove fuse 15. I think its 15, check the back of the cover to the fuse box. This will allow you to drive without the 4WD system powered up. It shouldn't switch automatically anymore, but you also lose your fuel gauge indication so make sure you know how far you can drive.

[chevelle]

Thanks for the reply somoney7. The dealer has told to me return the vehicle when it happens again. Do you recall where the 4WD module is located? Did you have yours towed in? Just curious how your dealer found the problem. I have heard from other Blazer owners of this same problem. The remedies have been the switch and the wiring harness to the trans.. This is the first time I have heard about a 4WD module.

Thanks again

[somoney7]

It is fuse 15 and it's labled 4WD, I checked. I had it shift on me while I was visiting my mom in San Diego. Luckily one of the dealers in town had their service department open. I figured out that once I shifted in to 2WD I could remove power to the 4WD system by removing fuse 15. Once I did that, I drove to the dealer and he told me about the 4WD control module and the switch. He only had the module in stock so that was changed out. I still haven't changed out the switch but it drives fine. Sorry but I'm not sure where the 4WD control module is located, but I hope some of this information helps.

good luck.

[chevelle]

Thanks again somoney7. Your info really does help. I know first hand how difficult in can be to repair something which doesn't happen all the time. From the responses I have had here and on another forum, this seems to be a common problem. Good luck with yours and please let me know if it happens again.

[somoney7]

Did you see this
http://www.automotiveforums.com/vbulletin/t94447.html

[chevelle]

Wow, thanks again. I didn't see that. I guess that answers a couple of questions.
1. Where it's at
2. Cost $600 bucks????

Good thing I have a warranty. I just hope this gets resolved before it ends.