4x4 High Light (Need Help)

[Mamba42]

Hello all, I have perused this site for quite a while and gleaned quite a bit of information from it, so thank you all for that. However, I have run into an issue that I am not able to solve with the threads that already exist on this topic.

Here is my situation: A few weeks ago I was driving home from Idaho and my 4x4 High light started flashing at me (I do not have a check engine light nor ABS lights). My 4x4 low still engages, but when there seems to be no difference between 4x4 high and 4x4 automatic (although the light does not flash when I press 4x4 high, it only stays on 4x4 high without flashing). Shortly after I got home I got onto this website and looked at possible answers. The first thing I did was check my fuses, and they are all good. Then, I ordered a new 4x4 Control Module (made sure it is the one for my VIN), and thought that would fix the problem... No luck, unfortunately. I then checked the ground wire on the transfer case shift motor, and it is in good condition, as is the shift motor itself. I then thought I'd replace the speed sensors on the transmission. To be safe, I decided to change all three (the TSS, ISS, and the OSS (although not the two rear OSS sensors located on the back of the transfer case). Changing the speed sensors did not fix the 4x4 high light flashing, but it did fix my transmission shifting issue which I was going to fix anyway.

Having tried all of these things, I am not sure what to try next. If anybody has a suggestion, I'd be glad to hear about it!

Thanks in advance!

 

[Mamba42]

Anybody have a suggestion? Today the 4x4 high actually does not work. So actually the 4x4 low is the only one that works. 4x4 auto and 4x4 high do not work. If anybody has a suggestion I would listen to anything!

 

[Mamba42]

Bump!

 

[Mamba42]

Hmmm, must be a serious situation on my hands for nobody here to have an answer!

 

[Limited02]

If you go out on gravel in 4x4 auto, will the rear tires spin? Check the #17 and 18 fuse under the hood.

 

[rmcknight]

the system will switch through 4*4 high to get into 4*4 low, so it shouldn't be possible to get what you are getting.
if you want to get dirty, pull the motor off and switch it by hand (with vice grips), and see if that sticks.

 

[Mamba42]

Hey -

Yes, on gravel my rear wheels spin out, both in auto and 4x4 high, though not my front wheels (which they should). 4x4 low, all four wheels spin out. Also, my fuses are all good, that was the first thing I did to diagnose the issue. That followed by ground wire check on shift motor, replacement of control module, and replacement of speed sensors.

I haven't tried that yet with the manual switch to 4x4 high to see if it even sticks. Could be worth a shot though. In any case, though, it's not that my 4x4 high won't "engage" according to the control cluster (as pressing 4x4 high eliminates the blinking issue and it simply shows 4x4 high), but the front driveshaft does not seem to be engaged in that mode. It's an odd situation for me.

 

[e19rze]

I had the exact same problem suddenly occur three weeks ago. I found that the transfer case shift control motor had an unconnected black ground wire. The wire had a stub end instead of a ring connector. I had no idea if or where it was connected to but after removing the heat shield I found a slight deformation on the transfer case land at the upper bolt. I temporarily connected a spare piece of wire to the ground wire and wrapped it around the upper bolt and everything returrned to normal. I'll now get another ring connector, shrink wrap, etc and make the connection permanent. You stated that your ground wire was in good shape but I'd suggest removing the upper bolt to determine if you really do have a good ground termination.

 

[Mamba42]

Hey all,

Thanks for the responses. I ended up taking it to my cousin mechanic and let him figure it out. Turns out that it was a bad shift motor. It looked good and shifted into 4x4 low, but the issue is fixed now.

In terms of the ground wire on the old motor, it was in good shape. I took the top bolt off and checked to see if it had any deformities, but it was fine. That does seem to be a common problem though, from what I have read. Thanks for the advice though!

Thanks for your help everyone!