After looking at the wiring diagrams again, I'd need to look a little further, but as far as the t-case is concerned, it's wired up the same way for the 95-96 as it is for the 97-02. I'd need to look at a pin-out of the two GEMs to know for sure, but a simple GEM swap from a later year may allow you to have 4 auto, 4 hi, 4 low. (I doubt the GEM is a direct swap though.... that's rare...)
Anyways, this will work better (in my opinion).
Most people clip the brown wire here:
That is up-stream of the splice with the other brown wire coming from the Transfer Case Shift Relay. It's the TCS relay in the 98-up that locks the transfer case when you put it in 4 hi. If you follow the harness up and around the vent ducting, you'll see the splice located on the driver's side of the compartment in the harness right behind the GEM module.
You'll need to unplug the GEM and remove the single screw that holds it in place to remove it. Remove the three plugs on the front, remove the screw on the bottom, pull the GEM DOWN and halfway out, then unplug the bottom plug. It's a lot easier than trying to wrestle the plug loose while it's still in there.
Then, you'll need to carefully cut back the electrical tape to gain access to the splice.
Gently remove the heavy duty wrap that is around the splice. You can pull a bit of slack up from the bottom plug to make it easier to work on.
You'll see three wires there. One coming up from the TCS module, one coming across from the passenger side TOD relay, and one going towards the driver's side to the transfer case clutch coil. MAKE SURE YOU CLIP THE RIGHT WIRE. For the 95-96, you DEFINATELY want to make sure you clip the output to the t-case clutch. For the 97-up, you can clip that one or the one on the other side of the compartment where it comes from the TOD relay. I'll explain more in a minute.
You can see which wire I chose to clip here:
I connected a SPDT switch wire up "backwards" so that I had two inputs and one output. Make sure that the output that runs to the clutch coil is on the center terminal of the switch. For the other input (and the other position on the switch) I pulled power from the cigarette lighter socket. It is rated for 20A and should be more than sufficient to power the clutch coil in the transfer case.
I installed a 15A fuse in that line as a back-up to the 20A that's already in it, and neither one popped last night during the trials. If you have a '95-96, you may want to choose a switched source to trigger a relay for this to prevent inadvertently leaving the switch on and burning up the coil/running the battery dead.
Here's the finished product.
If you have a 95-96, you can use just the second half (use a switched power source to trigger the coil) giving you full-time 4 wheel drive.
If you have a '97-up, you can use the first half to provide the disconnect for the transfer case, keeping it in 2 wheel drive. The advantage to cutting the wire where I did as opposed to doing it where it comes out of the TOD relay is that <i>it allows you to disengage the 4 wheel drive while in low range.</i> I tried it last night and it works like a charm, connecting and disconnecting the front axle on demand. If you splice the switch in at the standard spot by the TOD relay, when you shift into low range, the Transfer Case Shift Relay energizes the clutch and locks it in until you go back to 2wd.
Hope this helps someone!
-Joe
