Service 4WD light on dashboard

georgelb · March 29, 2017

Hello,

Hope this is the right place to post this. If not, my apologies.

I am having a 4WD issue, and I have tried several fixes from my father in law who is a mechanic, and Google and Youtube videos, and nothing is seeming to work to fix the issue. Hoping someone on here has experienced the same issue as described below, and can help me out.

I have a Chevy Silverado 1500 4x4 pickup. I live in Northern Virginia. When we had our last snow, I went to a clients house to remove some junk from their property. They had a dirt/gravel road, and still had some snow and ice on it. So I went to engage 4x4 to ensure I could get through it alright. When I hit the 4HI switch, on the selector, you could hear the truck switch into 4HI, but then the lights on the selector switch went off completely, and a "Service 4WD" light came on my message center on the dashboard. I figured something was wrong with it, so I tried to switch back to 2 wheel drive, because my truck already has 4 wheel drive issues (previous owners did something to it, and so when you go to make some turns in 4WD, it makes it seem the wheels are to their max turning point and will jerk).

Unfortunately, the truck would not go back into 2WD at all. After we did the job, I went to a nearby gas stations. Called my father in law and he said that it was stuck in 4WD and go back 6ft and it should disengage. I did that, and it seemed to work, as I could turn the turn in either direction, without issue.

I was able to make it back without issue. So, I assumed that everyone was fixed and it was nothing to worry about.

Went to get in it the next day, and still no lights on the selector. Didn't think anything of it, until I went to turn, and my truck was jerking pretty good (because of the previous owner screwing something up).

That is when my father in law told me that it was most likely the selector switch, but unfortunately, it could be 1 of 3 other possibilities as well. He told me to switch out the selector switch first, as it was the cheapest option, and generally the cause of the SERVICE 4WD light being on.

Bought a new one from Autozone. Installed it that evening, and when I turned the truck on, there was white lights for the selector switch, and not orange like my old one, but again didn't think much of it. Tried switching it into 2WD and NOTHING happened. Tried 4LO and Auto 4WD and again NOTHING happened. I figured I try again the next morning.

Got in it the next morning, and turned the truck again, and as luck would have it, no lights on the selector switch, except for a faint white light for 2WD.

So, I took it for a test drive. It is driving slightly better, but still has the turning issue to a degree but an improvement over how it was.

When I get back home, I go to back it up, and realize that now my truck as a reverse issue, and does the same motion, as when I make a turn.

At this point, I am at a loss, and so is my father in law (which never happens) as to what the issue is.

Everything I can find online via Google and Youtube, all say that the Service 4WD light on dashboard is for the selector switch and once changed, it will all work again, and no message. Didn't happen for me. Most guys on the youtube videos, even said that they changed out the transfer case, actuator, and the module thing behind the selector switch, but eventually changed the selector switch which was the issue to begin with.

At this point, I am at a brick wall. I dont have the money to replace it every component for the 4WD on my truck, as one part alone is around $1000. Only thing I can think of, is perhaps the selector switch is no good, even though it is new.

Hoping someone can give some insight or idea that we havent thought of yet.

Apologies for the LONG post. Just wanted to ensure that I fully explain everything that has happened so far.

bulldog52 · March 30, 2017

On my 2006 it was the shift position sensor inside the shift motor on the transfer case. I don't remember the code number that I scanned, but that seems to be a very common problem. I was able to remove the shift motor without dropping the driveshaft, but it was fingertips to remove the bolts.

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cprinci · April 11, 2017

What were the 2 other possibilities you were referring to? I've had some issues where when I start my truck, the selector switch has been in neutral, auto 4WD, and 4-Lo. Figured it was the switch (as I've read much the same) and took it to the shop. They took the transfer case off and indicated it was shot (stretched chain and quite a bit of damage on the inside). I ordered a new TC online, ($600 for 110,000 miles and 6mo warranty), and will be replacing it this week. Will advise of the outcome when I get it replaced.