Mystery 4x4 Issue

[Spbear]

Hi! I’ve searched but couldn’t find anything applicable to my problem. I have a 2006 EB expedition, and I recently had the rear end rebuilt in a local shop. When I got it back, the 4x4 wouldn’t work, so I replaced the transfer case shift motor. Turns out that wasn’t the issue. I have checked the wiring, I can manually engage the transfer case with the motor removed, i have checked the fuses, I have checked the selector switch resistance, and I have checked the relays behind the driver’s side headlight. When I try to engage 4hi or 4 lo, I don’t get any voltage to the shift relays behind the headlight.

Is my pcm fried? How can I test it?

Anything else I should be checking?

Thank you so much for your help, I am stumped..

 

[1955moose]

Since nobody here wants to say it, and I'm not shy. Go back to the shop that screwed it up! We can spend 30 posts here. But why! It was fine before, don't try to figure it out, they messed up, why should you suffer! If they deny it, go to consumer affairs, better business bureau.

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[Spbear]

I have been thinking about doing that, I just wasn’t sure if it’s possible that work on the rear end could have affected the 4x4 system, or if it’s just a coincidence that it failed at his shop.

 

[Wali4vr]

Moose Why would you ASSUME the shop repair of the rear diff had anything to do with a front diff engagement failure? They are completely independent of each other.
Spbear I'd start by putting the motor back on and put 12v to it to see if the new motor works. Good luck .

 

[Spbear]

Thanks for the reply. That was my thought too, I didn’t want to start pointing fingers if the two issues had nothing to do with each other.
I did apply power to the shift motor, and it does work. I have tried two new shift motors actually. It seems I’m not getting a signal to shift to the relays/shift motor at all...

 

[1955moose]

I'm not saying they did anything, but if you are 100 percent sure all was fine before rear end work, it's possible they josstled something when working in there. The fact that their an experienced shop, they should be able to figure out what happened much quicker than you. Unless your a seasoned technician and know what to look for. All they can say is sorry! Most reputable shops will check it out, due to good customer service. My shops that I ran would. Customer's coming back is Paramount in this business, not a once, take your money, and see ya!

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[Melanie Hoff]

I just recently got my Expedition and was told that my 4 wheel drive actuator is bad how much of that is true I don't know. Haven't had the weather to really test it out to make sure.

 

[SEPTIC PROFESSOR]

dude, just skip four wheel drive and take an uber on snowy days

 

[Jb14]

I just recently got my Expedition and was told that my 4 wheel drive actuator is bad how much of that is true I don't know. Haven't had the weather to really test it out to make sure.

You can test on the street put in 4wheel low you will be able to hear or feel the actuators engaged. Fairly easy fix if actuators but check the solenoid first and vaccum lines first. Might want to check out at different shop as well. Never hurts to get second opinion.