I need some advice. I recently bought a 1999 Z-71. 5.3 liter V-8. When I first start the truck it will usually shift into 4wd, but after a few minutes the "service 4wd" light comes on and it won't shift anymore. When it does shift, it shifts just fine. I don't know if it's the actuator or switch or something else. Any advice would be greatly appreciated.

Joshua

 

This is my first 4wd so Im having to learn as I go. But if anyone could point me in a direction to start at. I know actuators have caused problems for many people but I don't know much about 4wd systems. Please help.

 

Check the fuse and actuator.

 

i had a 99 gmc 5.3 z71 did the same thing. sometimes it would work until you hit the button then no lights and all of a sudden the service 4wd light came on. went on ebay ordered a switch for 40$ worked perfect after that.

 

The switch was my guess. And its the cheapest on rock auto.com. anyone had any problems ordering from them?

 

Before spending any money I'd check all the grounds especially the one under driver door on frame. I have three silverado's two with electric shift and one manual. On my 2001 1500 I had to replace the shift modual located behind the instrument panel on the left, Also replace the shift motor on the TX case. Went thru three of them before finding a A-1 cardone rebuilt. The switch was replaced but did no good. As for Rockauto, I use them alot as there prices are good and shipping is fast. Good luck

 

thanks for all the input. I greatly appreciate it.

 

i have a 1997 that started switching back and forth from 2wd to 4wd on it own and now its stuck in 4lo what could be the issue?

 

I am not sure what the actuator is but last weekend I went up to the mountains to play in the snow. I used my 4wd and by the end of the weekend it was acting up. When I start my truck, sometimes it will be in 4 low or hi or the little red light will be on and it always says service 4wd. If its in 4 low or hi I have to turn the truck off and then back on and hope it has shifted out. I have the Z71 model. Any help or suggestions would be appreciated. Thanks

 

For Brosebo it sounds like its the switch on the dash that is giving you problems. I have seen alot of problems like yours solved with replacing the switch the four wheel drive. Also for best results in getting a response, I would start a new thread about your problem rather than jumping in on one