Can someone with a 95 4x4 check?

[gijoecam]

Was there a switch on the '95 4x4s that had 2hi, 4 auto, 4 hi and 4 low? I might be thinking of the Expeditions)

If so, is there any possibility you could pull the switch and check the resistances in all four settings for me?

I'd appreciate it.

-Joe

 

[Blee1099]

On the 95-96, there was no 4HI option on the switch. It has been discussed many times before on this forum. Hopefully one day someone can investigate on how people with 95-96 can get 4HI. You can't simply switch out switches, the GEM module and other items also need to be replaced.

 

[gijoecam]

OK, so the 95s had 2wd 4 auto and 4 low? (still just 3 positions, right?)

The expeditions had a 4 position switch for a couple of years. My thought was (depending on the resistances and whether or not they match up) turning one spot into a dead open in the switch. After thinking about it, that would probably throw a fault code similar to clipping the yellow wire... Was worth a shot anyways.

My wiring diagrams don't go back beyond '96, but I'm scanning them now.... On the 96, the Torque On Demand relay is still present, so I'd run a DPDT ON-ON switch. I'd clip the brown wire like everyone else does, and use the switch to select one of two power sources: One side would be the TOD relay (from the existing brown wire you just cut) and the other side would be a 12-volt switched feed (so you couldn't leave it on when the key is off). That should allow you to let it do its automatic thing with the switch pulling power from the TOD relay, as well as engage the torque converter full-time by flipping that switch.

What do you think?

Here's another idea: If you use the on-off-on type of DPDT switch, and you spliced it in downstream of the splice in the brown wire where the TOD signal meets the Transfer Case Shift relay (I'm still trying to find out exactly where that splice is), you could theoretically engage the low range gearset with the dash switch and disengage the magnetic clutch coil that locks the driveshafts together with the auxiliary switch, thereby giving you 2wd low range too. You should be able to engage and disengage the front end in either high, low, 2wd, or 4 at the flick of a switch! Heck, that trick should work on the 98s as well, now that I think about it!

-Joe

 

[Crispy Niggets]

my 95 xlt auto 4x4 has a switch for 2wd 4wd auto and 4wd low
The way my manual explains it 4wdauto only provides power to a wheel if needed therefore saving on gas milage, 4wd low locks both systems to provide 50 50 in front and back

 

[gijoecam]

Correct, but in either case, it's the same transfer case with the same (or very close) internals that work the same way. When the TOD relay gets the signal from the GEM to engage the front axle, the signal is going to the same coil that locks the front driveshaft when shifting into 4 low. That's why I'm thinking that the switch that essentially bypasses the GEM should lock the TOD relay manually.

Still gotta work on finding that splice though....

-Joe

 

[gijoecam]

Found it.... did it the way I suggested above and it works like a charm, even for the 95-96.... it allows you to manually force the t-case into staying engaged. Tried it out and it worked like a charm!!

I'll have pics up in the AM.

-Joe

 

[gijoecam]

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