4x4 won't engage at all

[gmsux]

Last chance before I scrap the Explorer

I cannot engage 4wd high or low in my 2001 Explorer Sport. When the vehicle starts both 4 hi and 4 low lights flash on momentarily as they should. I have swapped in a new shift motor assembly and I still cannot engage 4wd hi or low. My Auto Xray scan tool does not register the 4 low request when I turn the switch to 4 low from 2wd with the engine running, transmission in neutral and brake on as is required to engage the low range. Hi range will not engage at any speed or in neutral etc. At this point I'm guessing it's the wiring or the 4x4 module. While driving I hear relay clicking noises every few seconds coming from the front passenger kick panel area where the 4x4 module is located. All the fuses have been checked and test OK

Does changing the shift motor require reprogramming the 4x4 module to synchronize the shift motor position sensors to the module??

Does anybody have a complete set of vehicle wiring schematics or at least the wiring for the 4x4 control circuits including the module i/o? I can trouble shoot as I was formerly an industrial electrician but without a schematic to analyze and a wiring color code assignment I'd be shooting in the dark so to speak.

Any help would be appreciated

 

[David Hutz]

Unplug and remove the motor.... clean the contact the contact points and reinstall. I have had to do this ever few years because corrosion builds on it the same as a penny that is not handled tarnishes. It should take you about 25 min total....
Good Luck...

 

[gmsux]

already did and still no go

It's also a no go with a new shift motor

 

[David Hutz]

Then I am at a Loss....
So sorry!

 

[gijoecam]

You need to see what the GEM is seeing for the shift inputs. Check the resistances on the switch to make sure they are within range for starters, but without seeing what the GEM is seeing in the system, it's a guessing game at best.

 

[Rudolph]

i REPLACED THE TRANSFER CASE MOTOR BUT NOTHING , WHERE IS RELAY ON 02 SPORT TRAC?

 

[gmsux]

transfer case control module is

I broke down and bought a set of factory manuals including the wiring diagrams book. They cover the 2001 sport and sport trac models although the 2000 is nearly identical and the 2002 most likely shares better than 90% , or even 95%, of the wiring of the 2001 models.

At any rate the 2001 model has the 4x4 Control Module (4x4CM) behind the passenger side kick panel. It has several data inputs. From the vehicle speed sensor, the transmission neutral selector switch, brake switch, 4x4 selector switch, communications i/o to the GEM module located inside the dash alongside of the drivers side of the stereo etc as well as all the position sensor inputs from the shift control motor assembly to tell the module what the position of the shift motor is as we shift from 2wd to 4x4 hi or low. i found that the new shift motor I bought had the motor fail after a single use. I have a new one now and will test it by plugging it into the harness but not mounting it on the transfer case. I'll be able to see it shift back and forth from 2wd to 4 hi and 4 low and verify it's operation before I mount it.

In short the old fashioned manually shifted 4x4 transfer case is a far superior and reliable set up than the electronic version. To date every sucessful engagement of 4wd has averaged out to about $55 per use based on the number of parts and time and labor involved. If this fails I will either build a manual shifter for it or rig a double pole double throw switch to the shift motor and work it that way thus bypassing the shift module garbage. only tricky part is knowing when to stop to hit 4hi since 4 low engages when the motor hits the stop at the end of the engagement cycle.

 

[gijoecam]

If you're still getting the blinking lights, the stored trouble code will generally pinpoint the problem. You're kind of trying to make a mountain out of a mole-hill by trying to circumvent the 4wd controls. The system is really quite reliable for the most part. It uses the GEM to process all the inputs (switches, brakes, trans mode, etc.) and triggers two relays with positional feedback from the contact plate on the motor. It's really quite reliable.

But again, if you're getting a trouble code, why not have it scanned to pinpoint the problem? It could be as simple as a loose connector or a loose pin inside a connector not making contact when it should.

 

[gmsux]

reliable??? not likely... Electric shift S*U*C*K*S*

my system has failed so often that it approaches a 50% failure rate. i'm on my third shift motor and second shift control module and I've hardly ever used it in 4wd. I've probably spent more than what the transfer case is worth brand new just fixing the electric control garbage. I doubt if it has even 200 miles on it in 4 hi for winter driving to work and on the farm. It has only been in 4 low 3 times to see if the thing actually would engage 4 low, once after installing each of the shift motors and once when I bought it to see if it worked. It has left me stuck in a muddy patch of ground once and stuck in wet snow once as well on a relatively shallow slope. It has been so unreliable that I bought a 2006 Jeep Rubicon Unlimited with a manual transfer case so that I can go out to the farm and not worry about a little mud patch or snow patch. Frankly an electric shift set up with so much interconnection to other control systems is overly complicated. Half a brain cell is all thats necessary to know to stop in neutral to engage 4 low as I used to do with my 87 Bronco and 80 international scout II.You don't need hundreds of dollars of computerized hardware and software to do that. It's the first last and only electric shift transfer case I'll ever own and if the case were to fail I'd replace it with a manual one even if I have to crawl under it to engage 4wd which is what I've had to do more often than turning the useless knob on the dash .

For the record I have it fixed as of today. The new shift motor I installed last week was bad. the brush wire burnt on the first attempt to engage 4wd so I guess that's 4 shift motors and 2 4x4CM modules. Reliable my ass

 

[gmsux]

PS my explorer is going up for sale soon.

Runs great looks great barely used transfer case LOL

120k miles, always garaged.

Brush gaurd two sets KC lights, 1 driving 1 fog, all available options i.e. power drivers seat, leather interior, power sun roof, power mirrors, deluxe 6cd in dash audio system with subwoofer etc.

All scheduled maintence performed.

new upper and lower ball joints using moog parts to make the uppers replacable and both upper and lowers greasable.

6cd indash replaced under warranty late 2007 (cd jammed in it)

 

[gijoecam]

Runs great looks great barely used transfer case LOL

120k miles, always garaged.

Brush gaurd two sets KC lights, 1 driving 1 fog, all available options i.e. power drivers seat, leather interior, power sun roof, power mirrors, deluxe 6cd in dash audio system with subwoofer etc.

All scheduled maintence performed.

new upper and lower ball joints using moog parts to make the uppers replacable and both upper and lowers greasable.

6cd indash replaced under warranty late 2007 (cd jammed in it)

I'll give ya' 2 grand cash. I'll even come pick it up for you. Deal?