I have a ‘98 XLT 4.0 4x4 automatic, last weekend the 4 wheel drive quit working, also the windows and door locks might be affected as they are only working intermittently now. Sometimes when I turn the **** into 4hi the 4x4 doesn’t engage and the 4wd lights in the dash start flashing. When I shut the truck off and turn it back on it will sometimes still shift into 4hi, I can hear the relay click when I turn the **** and I can hear the transfer case shifting, but will only shift into 4hi about once or twice before it quits working again. Once it quits working I no longer hear the relay click when I turn the **** and the transfer case does nothing and the lights start flashing again. Any ideas?

 

That symptom would be the shift motor starting to go out

The controller(GEM) flashes the 4WD lights when motor doesn't move when it sends the motor 12volts
In a 1998 there is a dual relay box behind the GEM module in the dash, if you hear one of those relays "click" then get the flashing lights the relay is working so it's then down to the shift motor, which is most common failure on the 1983 to 2000 4x4s
If you do NOT hear a relay click then could be bad relay box

All electric motors have common failure mode of not starting, they rarely quit while in use, they just won't START turning
i.e. starter motor, never had one quit while cranking engine over, when they fail they just won't START turning any more, well reliably, hit them with a hammer, lol

Same for power windows, one day they just won't START

 

To clarify, when the 4wheel drive fails to engage I do NOT hear the relay click. It’s completely silent when I turn the ****.

 

Then it could be the dual relay box, if 4WD lights were NOT flashing already, at that time the GEM won't activate the relay again, you have to key off and key on to reset it

If the 4WD lights flash it means the switch and the GEM are working
When 4WD switch changes voltage the GEM activates the relay and if motor doesn't move GEM will flash the 4WD lights, at that time GEM's 4x4 control is off line

Tap on the shift motor with a hammer or ??
If it starts to work again then swap it out

If it doesn't and still no relay Click, then replace the relay box, these rarely broke, its literally just 2 relays in a plastic box

 

Hey Ron, I have a 2002 Ranger XLT 4x4. Does my truck have one of those "dual relay boxes" you are referring to?

 

Think you've got the 4x4ControlModule behind the right KickPanel like my 2001 SportTrac;
an evolution from the prior years relay box, though likely not any more reliable.
4x4ControlModule & 4x4ShiftMotor in the 2001~20?? era trucks are both still NotoriousFailureItems.
Click here for more on the 4x4 1354 TransferCase + ShiftMotor + ConMod +...

 

Yep, I've replaced the 4x4CM twice and I'm wondering if it might be a wiring connection issue going into/ out of the 4x4CM... I saw a YouTube video about it a while back, now I can't seem to find the video anymore. I'm wondering if a faulty ground is the issue.

Does the GEM fail very often? I did get a code using ForScan that indicated a GEM issue. I did boost/jump start the truck a number of times in the past, I wonder if I fried the GEM with this boosting activity.

 

What specific TroubleCodes; write those down?
Can do a test:
* park+raise+jackstand vehicle where you can crawl under drivers door & get to 4x4ShiftMotor, set EBRake & block Wheels as needed to make safe.
* remove 4x4ShiftMotor, 4 bolts; leave wiring harness plugged in.
* have friend\wife in DriversSeat, Engine idling, foot on Brake, Tranny in Neutral, slowly move 4x4Selector thru 2WHi~4WHi~4WLo & back.
Watch 4x4ShiftMotor rotate.
If it rotates thru 3 positions correctly, likely a weak\failing ShiftMotor.
If it does NOT rotate correctly, likely a failed 4x4ConMod; wiring\ground fault less likely but might also be a cause.

 

I used my cheap code reader on my '02 Ranger, no codes came up. I then tried Forscan and three codes came up:

Code 1: (PCM module) Code: P1000 - On-Board Diagnostic (OBD) Systems Readiness Test Not Complete Module: Powertrain Control Module Diagnostic Trouble Code details On-Board Diagnostic (OBD) Systems Readiness Test Not Complete Follow the routines in the service manual to resolve the DTC listed. **any idea what's up with this code?

Code 2: (GEM module) Code: B1323 - Door Ajar Warning Lamp circuit failure Module: Generic Electronic Module Diagnostic Trouble Code details Door Ajar Warning Lamp circuit failure **I have noticed that my door ajar light in the instrument panel does not light up when the door is open.

Code 3: (GEM module) Code: P0500 - VSS sensor circuit fault. Module: Generic Electronic Module Diagnostic Trouble Code details VSS sensor circuit fault. Open VSS circuit. Shorted VSS circuit. This DTC may be caused by : Suspect VSS. Worn or Damaged VSS drive gear on transmission output shaft. Suspect PCM. Faulty or damaged instrument cluster module.

 

Ignore P1000, means EPA test cycle in progress & not yet complete after TroubleCode reset or battery disconnect.
Other 2 codes have nothing to do with 4x4 controls, though you should take care of those issues too.
Don't recall the PCM+OBD2 monitoring\alerting on much if anything on these 4x4Controls.

 

Ok so how do I solve the other two codes?