I am looking for a little information on the shift on the fly 4x4 system on my 97. After a search I have found some wiring diagrams and a little information, but I am having trouble locating the transfer case shift rely module. there is one box under the oval on the dash that is for the transfer case clutch, but I can't find the actual shift shift relay box. I am getting 4 wheel low just fine, but no 4 wheel high. When the selector is in the 4wheel high setting the transfer clutch relay just clicks. I am trying to locate the shift relay box to test the relays and the wires from there the gem, and to test for proper power and ground. Any helpful information would be thanked.

 

The first stop for the transfer case motor is 4H, then 4L.
If 4L works the relay supplying power should be good.
I would drop the transfer case motor and check out the circuit board and it's wiper contacts for an issue in it's first position or even a harness/plug issue.
This problem is rare where 4H fails and 4L is good.
There is an electric operated clutch to sync the gears for 4H to prevent grinding when moving.
The only difference is the position of the transfer case shaft moving the case drive to the low range when your stopped, in neutral and foot on brake.
Everything else stays the same in both ranges.
Good luck..

 

The motor is brand new the previous owner replaced it to try and fix this issue. Same issue with the new motor. It you shift the selector to 4 low but don't push the brake it will go to the 4 high position and show 4x4 on the dash. Once the brake is pushed while in neutral it goes into 4 low. The motor works fine as well as the indicator sensor in the motor. My problem my problem is that there is no signal sent to the motor when 4h is selected, the motor does nothing and gets no voltage. If you are in 4 l than shift it to 4h when in neutral with the brake on than it just goes back to 2 wheel drive.

 

Well I didn't know anything about the previous owner replacing the motor.
You never mentioned it in the first post.
4WD operation.
4H:
The dash switch signals the GEM module to rotate the case motor to it's first position.
This signals the fire wall solenoid to pass engine vacuum to the front actuator locking up the front axle and returning a signal back to the GEM through the case motor circuit board that turns on the 4H dash light.
Seems like there is an issue involving the GEM and the power relay that passes power to the case motor.
First question, dose the case motor run to the first position?
If no, it did not get power.
If it runs to the second position for 4L then the issue should be greatly narrowed down.
The operation is a bit complicated to describe over a board what all happens and to be followed by just reading.
You need service info to follow.
If you have not, look at the first 'READ' about 4x4
Good luck.

 

The motor does not move at all when switched to the 4 hi position. The only thing that happens when the switch is moved to the 4hi position is the clutch relay in the box under the cutout in the dash clicks until the switch is returned to the 2 wheel position or the 4low position. When put in the 4low position it will go into the 4hi position on the transfer and stay in 4 hi until it is put in neutral with the brake pushed down. I am kind of thinking that there is a problem with the gem module also being that everything else works fine. I just want to be able to test everything possible first before buying anything. Do you know the location of the relay box that powers the shift motor. There is the one right below the oval but the orange and yellow wires for the motor do not run to it. There is another relay box below it but I can't see the wire colors going to it. I have all the wiring schematics for this, I just haven't been able to 100 percent locate the relay box to test everything.

 

So no one know where the transfer case shift relays are located?