98 Blazer 4wd not working
 

Hey guys, I have a 98 blazer two door with 5 speed manual. When I push the 4lo or 4hi button it doesn't engage 4wd. The transfer case control module makes a tick noise and the lights on the 4lo and 4hi blink a few times. I replaced the transfer case switch for a new one, the actuator for a new one, and tried using a used tccm from a junkyard but I'm still having the same problems. Any suggestions?

Thanks guys

You can try looking at this page. My reply on the page is the 8th one from the top. https://blazerforum.com/forum/2nd-ge...05/#post675939

I checked most vacuum lines that are within easy reach including the one you mentioned that's located on the driver side fender. They're all properly attached and don't look rotten. Truck has 170k miles all california highway miles and has an excellent maintenance record.

You guys think it might be the tccm that went bad?

Even if they look good, the hoses could be leaking either from hairline cracks or being loose at the nipples. It is an easy afternoon fix and cheap to replace them. After 20 years, it is worth doing for the piece of mind.

Regarding the TCCM, I had mine go out at about 125k miles. The relays on the board I think just wore out. Unlike other electrical problems where the component either works for doesn't, my TCCM gradually got worse with the lights on my 4wd switch blinking a fair amount when it finally failed for good. It is not a hard repair to do. I found a good price on a NOS GM part on eBay.

Good to know, my 4wd acts up at times. Could it also prevent the transfer case from coming out of 4HI back to 2HI?

You know I'm not sure about your question. I think I remember my system getting stuck in 4wd and taking several attempts to get it back to 2wd. I'm sure someone else on the forum could answer your question better than I can.

A lot of people get a used one from a wrecking yard when their's breaks. If convenient and not too expensive, you might give that a try after you have tried other fixes. Foe my case, I knew I was going to keep my truck for a while so I got a NOS one. I think it cost me $80?

Well mine does get stuck on occasion, Guess I'll have to source up a spare to replace it eventually. For now it's not happening often enough to be a bother.

I confirmed that the actuator is not contracting. Any advice ?

look at it closely , it may be ripped...if its not check that there is vacuum going to it when 4x4 is selected.

encoder motor on the transfer case