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96 DODGE 4WD problem

Discussion in 'Truck & Equipment Repair' started by plowmaster07, Jul 3, 2009.

  1. plowmaster07

    plowmaster07 Senior Member
    Messages: 438

    Hi guys,
    Recently I was installing a brake controller adapter in the cab when two of the hot wires touched and sparked. It only happened once, but now when I shift in to 4wd, the light doesn't come on and nor am I really in 4wd. The front drive shaft spins but thats about it. Im hoping that someone else has any Idea where the fuse is, cause that would be awsome.
    Thanks,
    Aaron

    I have already looked in the fuse box right next to the battery and on the side of the dash board, and there is nothing for 4wd in there.
     
  2. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    I am not familiar with dodges, but since no one has responded, here's something you can try. Get a 12V test light. Turn your ignition on, and check each fuse with the lite. The fuses are designed so you can check for voltage on both sides, to make sure the fuse is OK. If you find one that lites up on one side and not the other, that should be it.
     
  3. BigDave12768

    BigDave12768 PlowSite.com Addict
    Messages: 1,446

    Ok first off one has nothing to do with the other. Wires sparking on a 96 has nothing to do with you being in 4wd. Yeah maybe you have a blown fuse, I doubt it. Ok first thing you need to is climb under truck on the drivers side just under drivers door. Locate the 4wd linkage. I personally had this same issue where my shifter was junk. Now check to make sure the linkage is connected to the transfer case. This is just one bar going back to it that moves it from gear to gear. You should be able to do this just by grabbibg the bar that goes back to it. While you are shifting this look and see how much play is in your shifter. If that spring is loose and flopping around you will need a new shifter. So check it for play. This is an easy repair but the shifter isnt cheap. Like 150 or so. One other thing if it just sort of siezed up you can remove the shifter and soak it in oil or Fluid film
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Like Dave mentioned your shorting of wires isn't connected to your lack of 4X4 function.

    If the front drive shaft rotates with the shifter in the 4X4 position (and you verified this while the truck was raised off the ground) then you don't have a transfer case issue, you have a front axle disconnect issue. Either you lost the vacuum source from the engine that supplies the 4X4 engagement system, the vacuum switch on the T-case isn't supplying vacuum to the axle shift motor, a vacuum line is disconnected at that shift motor, or the vacuum shift motor itself is defective. A little probing under the truck with a vacuum gage will narrow it down in a matter of minutes.
     
  5. plowmaster07

    plowmaster07 Senior Member
    Messages: 438

    Okay guys sorry it took me so long to get back to you. Landscaping's been really busy and I haven't needed the 4wd yet. So the vacuum actuator is still good (ohm meter check), It's the ground wire that is going to the vacuum actuator that is messed up. From what I've heard from a friend, dodge is famous for running the ground wire to the computer, which is true for the 4wd. I'm wondering if I can totally disconect the ground from the computer and run the wire right to the neg terminal on the battery, or can I splice the ground wire???

    Thanks for the help,
    Aaron
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    :confused: If you're still attempting to repair the 4WD indicator light you've placed the cart before the horse. Because if the 4WD doesn't engage then the light isn't going to illuminate. And the 4WD not engaging has nothing to do with any electronics/grounds/indicators etc...it's fully vacuum operated and needs nothing else to engage. It will work whether the ground lead to the indicator light from the switch on the actuator is good or not. And running that ground directly to the battery will do nothing but illuminate the light. Won't fix the engagement problem.

    So in a nut shell, you first have a 4WD engagement issue that needs diagnosed. And then worry about the light. It may work anyway once you have the 4WD operational.

    Need to dig into the vacuum system and it's components to see why the actuator isn't functioning, may be the actuator itself, the vacuum switch on the T-case, or a loss of vacuum between them or up to the port on the engine. A few minutes with a vacuum gauge and a look see for any damaged lines will tell you for sure where the problem lies.
     
  7. RODHALL

    RODHALL Senior Member
    Messages: 374

    I'll add a tad bit to this...

    CAD or central axle disconnect system is not locking the 2 peice axle togather.
    How the 2 peice axle works...
    2 peice axle gets connected togaher by a axle coller, it is moved by leaver that is run off vac...
    there are only 3 peices to VAC the system. vac switch on the transfer case, a vac accumlator and vac switch on the front axle.
    most of the time it is vac line.... so i just replace them all to know they are good from the get go...
    if that don't fix the problem then start looking at the vac switch on the axle housing.

    Oh and neither of the wires coming off the 4x switch on the axle housing is ground. ground for the switch is obtainted from the housing.
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Not on a twin wire switch. The black wire supplies ground to the the switch and then out to both the ABS controller (to let the ABS controller know that the truck is in 4WD) as well as ground the 4WD indicator in the instrument cluster on the outbound black/grey ground wire from the switch.

    PMaster thats why your Dodge buddy mentioned that Dodge was "famous" for running the ground trigger to the computer. Although it goes to the ABS controller...not the engine control module.
     
  9. Sealer

    Sealer Member
    from Ne, Pa.
    Messages: 47

    Listen to B&B. He's right. That light isn't going to come on until the front axle engages. Last winter my axle actuator actually "rusted" apart and had to replace it. If the driveshaft is rotating then it's not in your shift linkage or transfer case.
     
  10. plowmaster07

    plowmaster07 Senior Member
    Messages: 438

    Okay guys, now that I have finally had a chance to investigate with a diagnosis flow chart. It turns out that I have a hole right near the vacuum port down at the shift motor on the axle. I am trying to patch it, but if it doesn't work, then I'll be replacing it.
    Just wanted to keep you updated.
    Aaron
     
  11. plowmaster07

    plowmaster07 Senior Member
    Messages: 438

    Okay so it is finally working again! :) It turned out to be the vacuum actuator that was seized up. So I replaced that, the indicator lamp switch, and the transfer case switch. (Both switches were bad). I wanted to thank everyone who helped me figure this problem. And I wanted to wish everyone a very successful season!
    Aaron