Hi all,

I'm having a problem switching from 2WD to 4WD and back again when using the dash mounted selector switch. If I put the vehicle in neutral, select 4WD, and when the light is flashing, shift to park, it will engage 4WD. To get back to 2WD, the same procedure works. I got this from the owner's manual so this kind of tells me that this problem could exist even with a new vehicle. It mentions something "Transmission Indicator Switch" needs adjusting.

I can't find any reference to this switch on the web but have come across lots of other info that is quite confusing. TCCM modules, vacuum leaks etc.,

I am hoping some of the more experienced forum members could shed some light on the causes of this problem and how to fix it and get back to normal operation. I was thinking I could live with this condition, but why? It would mean pulling over to the side to shift modes when needed and here in Toronto in the past few days it has been needed. Surely cold weather wouldn't be a factor as this is one of the advantages of having 4WD where theres lots of ice and snow. Not to take away from all you lucky guys who need their 4WD in the desert.

Thanks for any help.

If it matters, it's a 98 Blazer LT Automatic, 4.3L

4WD Rookie.

 

I have the same problem, but with a '99. They tell me it is a relay that needs to be replaced. I will let you know after they do the work.

 

Hi just got my Blazer back. It took them 2 hours, but they started from the mechanical aspect, and worked up to the electronic, elimanting what they thought to be the small transfer motor. As it turned out, the reason for it not switching into 4hi, was the tccm module. Took them 2 minutes to change and I was off. I reside in Winnipeg, and we got a ton of snow this weekend. This was a quick, and inexpensive fix.Good luck to you and your 4x4.

E

 

I went through all that late last year. Ended up being the TCCM $$$ from the stealership. But I have Auto 4WD again!