Yesterday I was backing out of a parking spot at the store and it went in 4lo?Put it back in 2hi and now the 4lo keeps flashing for 10-15 seconds then stops for less than a minute and does it again.If I try to put it in drive while flashing it goes into 4lo.I have read some other threads and nothing sounds the same as this but I might have overlooked.I could really use some help on this please.I have to drive my daughter to childrens hospital on the 6th for surgery 220 mile round trip and no way will I take it like this.Thanks

 

Really not one person has any idea what's up with this?Come on someone anyone give me a clue what you think it may be.

 

4wd problems have been discussed extensively on this forum. A quick search will give you plenty to read through. You really are light on details in your post and reading through what others have posted will help you give us the detail we need to intern provide the support you request. And do not be so quick to dismiss seemingly unrelated posts just by the title alone. The Tech Article (DIY) section contains a wealth of information. Have a read through there as well.

First question... 3-button or 4-button switch on the dash? That should be the 2nd thing mentioned in EVERY 4wd related problem post.

 

I did the same thing recently. When you grab the gearshift lever its easy for your knuckles to hit the 4x4 buttons. I believe to get out of 4lo you have to be stopped in neutral or in drive going only a 1 or 2 miles an hour before it will shift out of 4 lo back into 2wd, Have you looked this up in your owners manual? I think they have a page on how to shift out of 4lo.

 

It's a 4 button switch and I didn't hit it but for whatever reason the 4lo just keeps flashing then stops and starts flashing again?Getting it out of 4wd was not a problem it's just very odd.I have read through the threads endlessly and see nothing like this.If you happen to know of one with this problem please point me to it.I have searched so many forums I cant remember them all.I have read about a few people tryng to put it in 4wd and it just flashes or a few lights flash and it wont go in 4wd.Mine wants to put itself into 4wd and does if I hit N while flashing.

 

Hmmmm, sorry but I don't have an answer for you on this one. If you do resolve this, please post what your solution was. This might help someone else down the road. Best wishes.

 

With the 4-button switch (NV236 transfer case), comes more involved diagnosis. A scan tool capable of communicating with the TCCM (GM Tech2 or equivalent) is required to access the TCCM and perform functional tests.

 

Ok I will go get it checked out and I'll post when I figure it out.Is there a way for me to just turn off the 4wd all together so I can still drive it.

 

I have a 2001 blazer. About two years ago, it started happening. It would automatically start wanting to go into 4-wheel low (it would start blinking and if I was going slow enough, it eventually would).

I noticed it started happening when it got warm out. It was fine all winter. It was easy to take it out by hitting the button to put it back into two wheel.

After fighting it for about a half a month one summer, it kept in two wheel. Then in the winter time, it wouldn't go into four wheel. Eventually, I got it, but it was frustrating. Then sure enough, once it got warm this past spring, it started doing the 4-wheel low thing. Eventually, I got it in 2-wheel and ripped the head unit out of the dashboard out of frustration. This suprisingly worked all summer.

From the research I've done, it could be the head unit in the dashboard going bad, it could be the vacuum, or it could be the whole motor that kicks in the four wheel. I've taken it to mechanics who never have a clue. Money not worth spent.

If you find out what it is, please share.

/regretting not doing cash for clunkers after tranny went, fuel pump twice in six months, and the door panels falling off. all at just about exactly 100k... grrrr

 

Mine did this and I pulled the switch and cleaned the contacts behind the buttons and it has been fine.