2nd Gen Control Trac Transfer Case Wiring

[HiImElvis]

Hey all,

Hopfully one of you can help me out with a wiring diagram of the harness that plugs into the shift motor of my 97 Sport? My 4 low is not engaging (I'm thinking it's the shift motor being stuck/ dead) since it worked one day but now it does not. Instead of thowing new parts at it, I want to make sure that all the "electroncs" are doing what they are supposed to and that when I actually flip the switch to 4lo the explorer is trying to shift, just can't.

There are 2 wires connected to each speed sensor (if anyone knows a correct Ohm or other measurement that indicates these are good let me know).

I also recognize the larger gauge brown wire as the one that likely controls the electric clutch/ differential or whatever it is that locks my driveshafts. together.

There's several other wires, if anyone knows what each one is for, and what I should see voltage/ Ohm wise between each of them and a ground I would appreciate the help.

Thanks!

 

[dogfriend]

The speed sensors are Hall effect sensors - they create a voltage when the magnetic field is disturbed at the end of the sensor - there is a tone ring (toothed ring) on the inside of the transfer case that the sensor reads when the front and rear driveshafts are turning.

You may want to remove the sensors and clean off any metal on the sensor end. They are magnetic so they attract any debris floating around in the TC.

Here is the pin out for the connector at the TC:

 

[dogfriend]

Here are the schematics for the control trac system:

 

[HiImElvis]

Thank you!

Thanks a TON!! Hopefully I can get under there with the meter tonight.

I appreciate the heads up on the Hall Effect sensors too. I hadn't considered them suspect per se (kinda figured I'd get a check engine light or my 4Auto would start freaking out if one of them went bad).

Nice picture by the way. My dachshund seems to like my 97 Sport as well.

 

[Bern]

Bad speed sensors aren't going to keep you from getting into 4LO. You have to be pretty much stopped, in neutral, and have the brake applied before it will even try.

 

[HiImElvis]

Problem Solved. Thanks Again for Helping Out!

OK, so it took me a few nights to sort it all out but my 4x4 system is now working properly. I checked all the wiring and all was well there. This was kind of tricky. I ended up putting the truck on jackstands and using blocks of wood to keep the brake and clutch pedals pushed down. Then with the ignition in the Run position I was able to move the 4x4 switch from position to position and confirm things were working.

Basically, it seems like if the motor is too weak/ dead to move at all and you were previously in High Range, it tries to move the motor for a few seconds then gives up and doesn't give you a 4lo light. I took the motor off and grounded it against the transfer case with the piece of wire I used so it wasn't hanging from the speed sensors and moved the switch (I had to cycle the ignition between off and run in between messing with the 4x4 switch). I was able to see the motor turning when I moved the switch.

I had a spare shift motor laying around that I had pulled off a buddy's wrecked 95 before he hauled it off to the scrap yard. I put that in and successfully got my truck to shift from High to Low and back to High. Being quite thrilled with my success, I messed around with the switch a few more times and managed to get the thing stuck in the Low range The next time I started the truck it was flashing both the 4x4 and 4lo lights at me (not good). So, now I was worse off then where I started stuck in low range and trying to move the switch wasn't doing anything.

I took off the salvage shift motor and discovered that the little knob sticking out of the transfer case had been rotated about 2/3 of the way between the Low and High positions. I used a pair of pliars to rotate it back to low and all the way back to high to make sure it moved smoothly. I'm not sure how hard that little guy is supposed to be to turn, but it seemed to rotate freely with only a minor amount of extra resistance just before it "popped" into either the full Low or full High positions.

I went ahead and replaced the transfer case shift motor with a spanking new one from NAPA (which requires you to remove the little red inner retainer to the motor side of the wire harness and use a toothpick to release the wires for each of the speed sensors). I could have just spliced them, but I wanted everything to look professional and all. After removing the wire leads from the old motor harness I used the pin out diagram supplied by dogfriend to push the leads through the back side of the new connector.

Once everything was bolted back together and plugged in I hopped in and turned the key. I was still getting the blinking 4x4 lights. I'm chalking this up to the junk motor making a partial shift between low and high before it croaked. It must have freaked out the GEM because it moved part way but didn't ever report back that it had finished the full shift. After disconnecting the battery for a few minutes and touching the + and - battery cables together I hopped back in and all is working as it is supposed to. The 4x4 trouble code from the GEM was gone and my truck shifts Low to High like it did when it was new.

So, I'm not sure why you don't get a flashing 4x4 light if the motor is not turning at all and you don't move out of the high range detent, but you do seem to get a flashing light to indicate a partial shift has taken place and your GEM has decided not to let your 4x4 system work any more, but Ford has done stranger things than this with these little trucks

 

[dogfriend]

The flashing lights just mean the GEM is seeing something that is not right. The shift motor has a set of plates inside that let the GEM know the position of the motor. So you are probably correct - the lights were flashing because the motor got stuck in an intermediate position.

Glad you got it sorted out.

 

[jzhoward]

Hey guys saw this thread and hopefully you can help! I have an 01 sport Trac. 4x4 is Not working. No lights, clicks, noises, nothing! As I was changing the oil today, I noticed some wires cut just under the driveshaft ON the transfer case. This HAS to be the problem however, I'm not sure what these wires went/go to. The transfer case (TC) motor and plug and all seem to intact and all looks ok. The three wires directly under the driveshaft on the transfer case and one lone wire just to the left between the TC motor and the driveshaft. I can email a pic if necessary. Anyway, just trying to figure out where these wires are supposed to go!! Thanks for your help/suggestions!

Zach