First of all the topic of this post is about my 4x4 not engaging. I have a 2001 xlt which has the electronic 4x4 switch. Just the other day it will not engage into 4 high or low and no light on the dash and it actually does not engage. I checked all possible fuses and they are all OK. What else could be the problem.

Before this problem, pertaining to the same thing, my transfer case is dead; it clanks and grinds and is destroyed inside. So its possible also that the xfer case is so 'dead' that it physically cannot engage and that is causing the whole 4x4 problem to begin with. Any help!!?? I live in Erie, Pennsylvania which is covered in snow and ice all winter long and NEED 4x4 to go anywhere.

 

Do the 4wd lights light up when you start the truck? If not then more than likely the 4wd control module is fried.

And if your t-case was internally blocked from shifting into 4wd then you could have fried the motor as well.

 

most likely the 4x4 pcm, if it was the engagement motor, you would have the 4x4 motor fuse blown, happened to me.

 

Most likely actually the limit switch inside the motor and gear assembly. Extremely common problem.

Look here: http://www.explorerforum.com/forums/...d.php?t=123542

One of the best articles explaining what's usually wrong and it's not the motor or controller most of the time -- it's the stinking feedback rotary switch.

 

This may come in handy with the Exploder I'm driving.

Sidetrack, I picked Matt (99Ranger4x4) up from the airport last night since his flight into Laramie was cancelled due to snow. Sitting in a drive thru, we started playing with the 4wd switch cause it wasn't lighting up (93 Exploder, old push button style) but we kept hearing a relay or soloniod snapping in the back of the Exploder, which brings up a point, is it possible the relay could be shot and sending the wrong amount of power to the motor???

 

Yes, but it's more likely something else. There are two relays that are used when you shift.

One relay engages a solenoid the pulls in a clutch to get the front axle moving before the "hard" engagement happens from the motor. The other relay kicks in the motor to move the system. Once you are in 4 HI by the motor, the solenoid releases. The solenoid is activated by the brown wire that goes directly into the transfer case. On AWD transfer cases, the brown wire controls the modulating clutch in the transfer case for torque control.

Hard to say if that's just one relay or both. You might still have a good motor. If you read that write up they tell you what wires go to the motor and you can try driving the motor directly with 12 volts to see what happens. Disconnect the wiring harness to the truck first though.

A blown fuse for the motor power circuit, or similar problem would also cause those symptoms. The controllers have separate power feeds for the logic board and the power to activate the motor/solenoids.

Attached are the schematics of your control system if that helps.

 

What and where is the 4x4 pcm? When switching from 2 to 4wd I cannot hear any relays or any attempt for it to try engaging, so i'm guessing it's something electrical. And as I have said, no fuses blew.

 

It's in the passenger side kick-panel. On the side of the passengers footwell behind the plastic piece on the right side.

It would probably not make any noise if the limit switch is too far to one side also.

Been driving like me, Joe, and getting stuck in deep water?...

I'll grab the schematics on yours as well and post them. Stand by...

 

Here you go, Joe.

 

...haha John I have been in some water in the past, but not recently. I'm sure I can find the module now, what do I check for with the schematics? I haven't looked at the module yet.
Thanks for the schematics by the way.

 

Awesome. I read the article, very helpful. Walked through a few steps last night and found both the Explorer and my buddy's Sport Trac's shift motors are stuck. So, soon as my Ranger is back on the road, I'm gunna let my buddy borrow it for a day and I'll work on getting that motor fixed. The Exploder I'll do on my own time as well. I'll save those schematics, real helpful!

 

Last night I took off the shift motor and took it apart as the write-up went through and put it back on. Before I put it back on the transfer case I ran power to it and it does work, so aparently it's not the motor. I checked all fuses and relays, so what else can it be?

 

Ummmm, I'm not quite sure WHY you are even ASKING this question.....

 

Ha ha! Well, he's thinking that maybe partial engagement or whatever is causing the noise.

Question, Joe: Did you index the control shaft all the way to 4LO to see if it works? Most of them won't manually stay in 4HI without the motor to hold them there. The "stop" the shaft drops into is "neutral" and you get nothing.

So, taking the motor off, and turning the shaft coming out of the tcase all the way one way should give you 2HI with no internal noise. Turning it all the way the other way should put you in 4LO and once again, it should sound fine.

If these tests result in transfer case problems, then the case itself is the problem.

 

I'll add that IF John's advice works for you (meaning your TXFR case is still good), your 4x4CM should have a label with #'s on it like:

Ford Part # 1L54-7H417-AC
Vendor # M799G
Motorola Model# 01MP207C01
and a Date Code and serial #


I know because I have my buddy's bad one sitting here on my desk, from his 2001. They are a common failure item. Many folks have reported (especially Explorers) that the 4x4CM failed after simply replacing a dead battery.

My buddy's failed after he gave his other vehicle several jump-starts, IIRC.

 

I did not index the control shaft to 4LO, which I can try tomorrow. Is it possible to move the triangular shaped control shaft with a wrench or should I 'hot wire' the engage motor to it? The shift motor is fine; I hot wired it and it works fine, it just doesn't work via the normal cab control switch as it should.



And, Earl34P, where is the 4x4CM that you're talking about and how do I know if it's bad or not?
I'm guessing that the problem is the 4x4 control module because the shift motor works fine, but the cab switch does not make anything happen which means that it is an electrical problem.

By the way, thanks everyone for your help! I hope I can fix it soon!

 

You can move the shaft with a pair of pliers no problem -- or at least, you SHOULD be able to.

The one he's talking is the one in the passengers side footwell behind the kick panel.

 

I told you this before. Check to see if the 4wd and 4low lights do a self check when you start you truck.

 

The 4HI and 4LOW dash lights DO NOT illuminate when starting the truck when all of the other lights do, so I guess it is the 4x4 module.

 

More than likely yes. The 4wd PCM and switch burn up on me. And I didn't even blow the fuse! I have part numbers for the switch and PCM at home if you need them.

But just to double check, have someone turn the **** while you are under the truck listening for the motor engage. As a matter of fact you canprobably hear it if you don't have the engine running.

 

I just took the control module out and switched it with Rudeman85's and both of them do the same thing; aka the 4x4CM is not the problem. I'm going to try the actual switch **** right now, i'm going to hot wire the wires and see if the switch is bad.

What and where is the switch you are speaking of; do you mean the cab **** on the dash?

The motor does not engage and nothing does anything with either module plugged in.

 

Yeah. Its the selector switch inside the cab.

I wish I had a manual T-Case.

 

I'm lost, I have no idea what else it can be.
The switch, control module, and 4x4 motor are all fine along with all fuses and relays. There is some electrical problem somewhere that I cannot detect.

 

Try separating the main connector under the truck. See if the contacts are dirty.

 

I had the main connector apart when I took the motor off of the xfer case; the connector inside was extremely clean, I don't imagine it causing any problems.

Are there relays for the motor and such in any other place other than the main fuse panels? Normally when the 4x4 works there is an audible relay that switches on that sounds to be coming from the passenger side kick panel where the control module is. Is there another relay other than just the control module itself? ...Because I do not get the relay click when attempting to use my 4x4.