You are here:

4 Wheel Drive/SUVs/4wheel drive on 1999 Z71 chevy silverado


my 1999 4wheel drive wont engage.the light just flashes on an off but wont go in 4wheej drive


Seems to be a common enough problem - either the module with the switches (go to a scrap yard to get a replacement to see if that helps solve the problem for now while you order a new one) or; the actual actuator for the 4WD is faulty.

You can remove the actuator and watch it while somebody puts it into 4WD. If it doesn't move then I would buy a new one and replace it.

Another possibility is the actuator on the front diff was went out. They can short out and burn out the electronic shift unit on the transfer case.

These are the most common problems with the Chevy 4x4's.


4 Wheel Drive/SUVs

All Answers

Answers by Expert:

Ask Experts


Carl Brandt


Will discuss suspensions, lifts, lockers along with tire suggestions. Trail ratings and possible requirements needed for specific type of trails. Safety equipment and what you should carry with you. Certified off-road instructor. I am not a mechanic, and 4-Wheeling is a hobby, so if I can't answer a technical question it is due to my mechanical knowledge being related to vehicles that I have owned, or have worked on. I do not have manuals on all vehicles, and I suggest that you obtain a repair manual for mechanical problems and do some research before asking your question. Most mechanical questions can't be answered completely without looking at, or listening to the vehicle in person.


40 plus years of 4 wheeling in a variety of vehicles. At the present time, my major off-road rig is a 94 Jeep Wrangler with a spring over and a 1 1/2" suspension lift. This gives me a total lift of 7" or so. I have lockers front and rear. I have removed the track bars, and sway bar for maximum articulation. I am running a stock 2.5 ltr 4 cylinder with a Jacobs ignition along with a cold air high flow filter. It has 4.56:1 gears with a Dodge NV4500 transmission along with a 3.8:1 Atlas II transfer case. This gives me a final ratio of 105:1 in low gear/low range. Other vehicles I own, are a 96 Ford F-250 with a 6" lift, posi rear end, 36" Hummer tires, 5 speed with a fuel injected 460 ci engine, an 87 Samurai with an 8" lift, Ford 9" rear end with a spool, Chevy Dana 44 front end with an electric locker, 5.88 gears, 16% reduction in high range and a 6.5:1 low range with 35" Baja Claws, and a stock 2003 Grand Cherokee Overland. Trails I have run are the Rubicon (10 times), Dusey Ershim, Fordyce Creek trail, McGrew trail, several trails in Moab, Utah along with local monthly runs.

Lost Coast 4x4's Cal 4-Wheel Corva UFWDA Blue Ribbon Coalition

Certified off-road instructor - Certificates in engineering/electronics

©2016 All rights reserved.