Sorry if this is a bit redundant, I've done lots of searching and could not find an answer. I bought my '04 1500 silverado Z71 new and since then the service 4wd light has came on about three times, with the lights on the 4wd switch shutting off. I would shut the truck off and start it later in the day and everything was fine. Happend again about two weeks ago, but the switch lights never came back on. I pulled the fuse's which took care of the service 4wd light but did nothing to fix the problem, switch lights are still off. Everything I can find points to the switch in the dash, so I buy a new one ($65) thinking thats the problem, put it in tonight and still nothing. My next step is to see if I have power to the switch. Other than that I'm lost. When it first happend I did take it back to chevy and they said nothing was wrong. Now I'm out of warranty, yaaayyyyy. Any advice would be appriciated. Thanks

 

The actuator solenoids(and I'm sure GM muddied the waters by giving them a fancy new name) on automatic or "pushbutton" 4WD tend to bind if they're not used regularly. This causes these systems to fail on a disappointingly regular basis.

The service light uses a sensor or a switch, just like all the other warning lights on your dash. (Does the 4WD itself actually work? ) If you can trace the wiring on your 4WD unit to this "switch" you could possibly straighten out the problem.

Be sure to do all your 4WD system preventive maintenance. Perhaps your transfer case or front differential fluids are low.

Finally, not that it helps you with your truck now, but consider it an expensive lesson learned.
There's a reason most the serious 4WD crowd has manual 4WD shifters. If the sleek,sexy, pushbutton 4WD controls were anything near dependable, we'd all have them, too. In the future, if you decide to go with 4WD, (if you don't need it I can't recommend it) be sure to INSIST on a manual 4WD shifter, NO MATTER WHAT THE SALESMAN SAYS.

 

The 4wd does not work. The truck is a stock Z71, not a serious 4wd'er, but I do live in the snow and need it in the winter. All fluids are good and have been changed in the last six month's. I put the truck in 4hi for a couple miles just to exercise it a bit,(hasn't been used in 4 month's or so) the next morning start the truck and no 4wd. When I bought the truck I did not know manual 4wd was still available, I would have requested that. Where would these actuator solenoids be, diff, t-case? I realy want to avoid bringing it to the dealer, I haven't won the lottery yet.

 

Hey, don't sell your truck short, all those poor b@$tards going to work in their Geos and Prius's everyday are watching you pass with a tear in their envious eyes. Z71 packages make for an impressive head start for serious off-roading.

They should be above your t-case, right about where a manual shifter would be if you had one. The annoying thing is they can test fine after you jog them around a little, but you let them sit for a couple weeks and presto!(But you probably wouldn't call it magic...) If you replace them, run that 4WD unit for a few seconds every three days or so, it helps, but the new parts aren't that much better than the old ones.

I would recommend finding a manual which covers these

pushbutton shifters before you start the job, or alldata.com

 

There is power to three of the seven wires on the big plug and no power to any of the four wires on the small plug(dash switch). Not sure whats normal. Pulled all plugs on t-case and front diff and cleaned them. The transfer control module is not where my manual (chilton) shows it. Still havn't found it. Guess i'll have to break down and have it put on a computer.Thanks for the help

 

have found out that usually the two ground wires that are attached to the frame right under the front of the driver’s door is the culprit that causes the 4wd selector switch in the dash to go bad. Chevy had the bright idea of applying the undercoating and/or not cleaning the point of contact of the ground wires before they bolted them to the frame therefore overtime moisture, dirt and corrosion affects the contacts of the threads of the bolts which are the only source of ground the two sets of wires have. There are 2 things you will need to do. First you will need to take the bolts out and use a wire brush to clean down to the metal of the frame as well as the bold threads and ends of the wire attachments and then reattach the ground wires to the frame (time to complete – less than 5 minutes). Second you will need to replace the 4wd selector switch in the dash. You can purchase this online from Amazon (Dorman 901-062 4-wheel drive switch for $31.15 – no tax or shipping and handling). To replace, gently pull the outer trim of the dash out by using just your fingers. You do not need to completely remove it, just pull it out far enough so that you can pull the old switch out of it slot. Then unplug the two plugins located in the back of the switch. Plug them into the new switch and push the switch back into the slot and then push the trim back into place (time to complete – less than 5 minutes). This should take care of your problem. Most often, people make the mistake of just switching out the dash switch and when that does not correct the problem they then replace the more expensive and time consuming actuator motor and location indicator on the transfer case that does not need to be replaced. I should point out that when the Service 4WD light comes on, there are no codes that show up on the code readers which is awful strange in its self. I hope this helps everyone with this problem because I sure wish I knew this before my many costly and time consuming trips to multiple repair shops

 

P.S. There are two types of switches pending your transfer case mine is actually 901-072. Just look at the pictures lol.