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  1. #1

    Default 4 wheel drive not working

    i have a chevy 1500 4x4..i snaged the wires on something under the the 4 wheel drive won't engage..there is switch on the dash that was lighting up now it won't. there is wires running to what looks like a switch or something on transmission..or there a diagram or something i can look at about wiring?i hope this isn't confusing thank you for looking.

  2. #2
    Sr. Apprentice WARLOCK's Avatar
    Join Date
    Nov 2011


    Look on the internet for wiring diagrams, you should be able to find one.

  3. #3


    You have a relay that switches the transfer case. You may have a wiring issue, so check that first. The relay may need to be replaced. Relatively simple process. Order one from your dealer after you take yours out and test it.
    1994 Chevy K2500 Silverado, 454 (modified), original owner.
    And other vehicles and toys.

    "...If you can meet with triumph and disaster
    And treat those two imposters just the same;'ll be a Man, my son!" Rudyard Kipling

  4. #4

    Default 4x4

    hey thanks for answering...i am not much of a mechanic,so hope you don't mind me asking questions. where is this relay? i can look under the truck there is i two sets of wires,one going to top of trransfer case,the other to the actuator. now can the actuator be bad or i just got the wires messed up. i plugged one of the wires back in and the other the plug was pulled off so i twisted them back together....nothing.i know it has got to be something simple... thanks

  5. #5


    Sorry for misstating the part. I am talking about the actuator. It works similar to a relay, just a different name. It is like what you have in your doors to work electric door locks. Magnetic function upon application of electricity.

    Joe, if you don't have one, go to Sears, go to tool section and buy one of the volt-ohmmeters they have for sale. They probably are labeled as "multi tester" or possibly "voltmeter". Depends on how much money you want to spend on one. The Fluke and OTC (not sold at Sears) are tops, but you don't need one that fancy, just a plain old analog readout will work. Put the leads on the two wires, switch to DC volts, with probably the 50 volt range, and have someone move the four wheel drive switch or lever in your truck with the ignition on. See if you get a signal. It should read around 12 volts. If it reads low like 7.4 volts, etc, you have a crummy wire connection somewhere. Not going to belabor that point here without more info on what your situation is, but assuming you get that good voltage reading, the leads go on a certain way to work the actuator. If they are backwards, it probably does not work. Make sure you have the correct connection.

    Best for you to buy a service manual with wiring diagrams and pictures to look at. Saves you time. I own the factory manuals for my truck. I recommend getting those (try eBay if you want to shop for a good price). Short of that, you can get a Haynes manual which has wiring diagrams and electrical instructions, maybe even a procedure to test your actuator (they design instructions for the home owner, not a pro mechanic). Ebay, or Amazon to buy the book on line.

    There is also a professional wire lead kit to use with electrical testers that has been indispensible for me on all electrical trouble shooting. It has stuff to hook up to wires in different situations, plus extensions to attach to the leads of your volt-ohmmeter to get hooked up to stuff far apart, etc. You can get one at The Tool Warehouse. Have bought LOTS of automotive tools from them.
    Last edited by The Heater; 11-22-2011 at 02:22 PM.

  6. #6


    I bet that it is the actuator on the front axle differental. Pretty common to failure.

  7. #7


    x2 on the actuator failure. You can just get a big wrench and unscrew it. then engage the 4x4 and see it the rod in the center of the actuator moves. if not it is time for a new one. They are around $60 I think. Or you can put a Posilok on it, that eliminates the electrical actuator and makes it a manual cable. Those run around $100. The advantage of the posilok is you can out the transfer case in 4 low and not engage the front axle. Essentially giving you 2wd low. Great for times that a lot of torque and not alot of traction are needed. I run 2 low at the sand dunes. Lots of power to climb and I don't break traction so I don't need 4wd

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

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