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4 Wheel Drive/SUVs/electronic 4x4 not working

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Expert: - 12/1/2006


Question
I have a full size 1989 ford bronco with the electronic locking 4x4. I have a repair manual but it doesnt seem to be much help. When i push the button nothing happens. the 4x4 light will not even come on. it will not even try to shift into 4 wheel. everything else is working fine, except that. I took the 4x4 switch out of the dash and tested for power and the only power i get is from the illumination wire when i turn my headlight switch on. Is there a seperate fuse that runs the 4 wheel, or could this be a elctronic control problem, i have worked on it for 3 days now and just cant find the power source for the push button switch, if you could give me an idea of what it could be it will be greatly appreciated, thanks.

Answer
Jerry,

I would start at the transfer case, and start checking the wiring, and making sure that the transfer case has a good ground.  From there, I would start tracing wires to see if you may have a broken one, or bad connection.  Your manual should give you some color codes and test points in the wiring diagram.  If you are having problems with this manual, you might see if you can find better information in another manual such as Haynes, or Chiltons.

Carl

4 Wheel Drive/SUVs

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Carl Brandt

Expertise

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.

Experience

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.

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

Education/Credentials
Certified off-road instructor - Certificates in engineering/electronics

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