TC Shift Motor no power from harness 98 explorer

[CaseyMac]

I am working on my 98 explorer XLT with the 4.0 V6 SOHC and I removed my TC shift motor to test to see if it will switch between the 4X4 settings and it doesn't move. I have also tried testing the harness to see if the motor is even getting power and I am not getting any readings on my multimeter. I have checked all fuses and non are popped. TC is stuck in 4 HI and I can't get it to go back into Auto. I tested my switch in the dash and it is getting power. I even tried replacing the GEM I pulled from a 2000 XLT model with no results. If I am getting no power through the harness where is my next area to check? I have tried searching the threads but only can find info on replacing the TC motor or telling someone to test if it is getting power but not following up with what to do if it isn't.

 

[elrothir]

Casey,
I believe that shift motor grounds itself to the mount. So, if you pulled it off and let it hang and then turned your 4WD knob, it probably wouldn't work because it's not grounded. And, if you're testing for power on the harness, I think it'll only register power when the knob is turned and the motor tries to shift. It probably won't have power running to it all the time. So, I think you'd need to have someone turn the knob for you while you put your red connector of your multimeter in the harness and then the black multimeter lead to the chassis and see if you get a reading.

Were you getting the flashing O/D, 4Lo, 4Hi lights too? I saw your post in my thread, so not sure if you're getting the same symptoms.

You say the post on the TC is pointed to H. Can you grab a pair of pliers and try to manually turn that post to N or L? If it turns easily, it's probably something with the shift motor. If you're not able to turn it, you might have a problem with your transfer case. I think when I had the issue, they said you might have to have someone push on the car(with it in park) to release any pressure on the TC while you try to turn it. If you're on flat ground, it might not be an issue. I was able to easily turn mine when it was on flat ground, so mine ended up being a bad shift motor.

Hope that helps.

 

[CaseyMac]

Casey,
I believe that shift motor grounds itself to the mount. So, if you pulled it off and let it hang and then turned your 4WD knob, it probably wouldn't work because it's not grounded. And, if you're testing for power on the harness, I think it'll only register power when the knob is turned and the motor tries to shift. It probably won't have power running to it all the time. So, I think you'd need to have someone turn the knob for you while you put your red connector of your multimeter in the harness and then the black multimeter lead to the chassis and see if you get a reading.

Were you getting the flashing O/D, 4Lo, 4Hi lights too? I saw your post in my thread, so not sure if you're getting the same symptoms.

You say the post on the TC is pointed to H. Can you grab a pair of pliers and try to manually turn that post to N or L? If it turns easily, it's probably something with the shift motor. If you're not able to turn it, you might have a problem with your transfer case. I think when I had the issue, they said you might have to have someone push on the car(with it in park) to release any pressure on the TC while you try to turn it. If you're on flat ground, it might not be an issue. I was able to easily turn mine when it was on flat ground, so mine ended up being a bad shift motor.

Hope that helps.

Yes, all 3 of the lights flash when I had the harness plugged into the TC shift motor but only the O/D light flashes when I unplugged the motor. I grabbed pliers and tried to turn it but it felt like something was pulling on it, like it was spring loaded because when I let go it popped right back into the "H" position. I didn't think about the grounding. I will run a wire and ground it out to check. I will see if I can do the power test when my wife gets home and have her turn the knob while I check the harness. But then again if is supposed to be in the "H" position I wonder why I can't pick up speed past a certain point.

 

[elrothir]

I believe when those lights are flashing, it's in 'limp mode', so it won't let it shift properly and gives you the high RPM/low speed.
Is yours on flat ground? If it is and it's difficult to turn the TC from H to N, that sounds like an issue with your transfer case. If you can't easily turn that rod, the shift motor won't be able to turn it either and that may be why it's flashing the lights.

You could try to put your switch on 4WD High and then disconnect the battery for a bit. When you reconnect it, it should see that the switch is in 4WD High and that the shift motor is in 4WD High, so it might think all is ok. Then try to drive it and see if it lets you get above 45MPH. If it works, that at least gets you running, but you probably still have an issue with the TC.

 

[CaseyMac]

I believe when those lights are flashing, it's in 'limp mode', so it won't let it shift properly and gives you the high RPM/low speed.
Is yours on flat ground? If it is and it's difficult to turn the TC from H to N, that sounds like an issue with your transfer case. If you can't easily turn that rod, the shift motor won't be able to turn it either and that may be why it's flashing the lights.

You could try to put your switch on 4WD High and then disconnect the battery for a bit. When you reconnect it, it should see that the switch is in 4WD High and that the shift motor is in 4WD High, so it might think all is ok. Then try to drive it and see if it lets you get above 45MPH. If it works, that at least gets you running, but you probably still have an issue with the TC.

Ok I think I will put it up on jack stands and see if I can turn the knob. I wasn't able to test the shift motor yet and probably will have to wait to the weekend. I am in the Army so my days are pretty long and I don't have the light by the time I get off work. I have a few issues with my explorer I am trying to get taken care of but one step at a time I guess. I have some of my gauges on my cluster not working either and one of the codes I am getting is the P1260 - Engine Disabled by (PATS) however, I have no problems with it starting up and running.

 

[J_C]

The motor only has two positions, high and low. If it is in high, that is the same position it would be in for 4hi/auto.

The motor does not ground through the case. Which high/low position it is in is achieved by reversing the polarity of the power wires going to it, making one positive power and the other ground to switch one way, and then reversing their polarity through the Shift Control Module to make it shift to the other high/low position.

Both of those wires are normally grounded, then the Shift Control module switches one or the other to 12V depending on which way it is supposed to shift.

It will only receive power for the moment it is changing position. You can check whether the Shift Control module is outputting this power. It's in the dash, behind the radio IIRC. The orange and yellow wires are the two which power the shift motor and reverse polarity.

You should also check the Shift Control Module's connector black wire, resistance to chassis ground, should be near 0 ohms, and there should always be 12V on the dark-green/light-green wire to it. If there is not 12V on that wire, or perhaps the first thing you should check instead since it's easier, is the fuse #6 in the under-hood power distribution box. See circuit diagram attached.

If the Shift Control module is getting 12V on the dark-green/light-green wire but not outputting on the yellow and orange, then I'd use a multimeter to measure the resistance the dash shift switch module should have in each switch position as shown on the diagram, that it should have between the white/light-blue wires and gray/red wires in each position (approximately): 3.9K, 1.1K, and 360 ohms.

If you wanted to test the shift motor directly, you could unplug the connector to the Shift Control Module, and apply 12V to the yellow and orange wires for a brief moment. Make one of the wires positive and the other negative then do the opposite, making the other wire positive and negative.

With the motor detached, note which position it is currently in first, then you should have it shift at least one way or the other if not both, then remember to shift it back to the position that the transfer case is in which you reported as being high mode right now.

 

[CaseyMac]

The motor only has two positions, high and low. If it is in high, that is the same position it would be in for 4hi/auto.

The motor does not ground through the case. Which high/low position it is in is achieved by reversing the polarity of the power wires going to it, making one positive power and the other ground to switch one way, and then reversing their polarity through the Shift Control Module to make it shift to the other high/low position.

Both of those wires are normally grounded, then the Shift Control module switches one or the other to 12V depending on which way it is supposed to shift.

It will only receive power for the moment it is changing position. You can check whether the Shift Control module is outputting this power. It's in the dash, behind the radio IIRC. The orange and yellow wires are the two which power the shift motor and reverse polarity.

You should also check the Shift Control Module's connector black wire, resistance to chassis ground, should be near 0 ohms, and there should always be 12V on the dark-green/light-green wire to it. If there is not 12V on that wire, or perhaps the first thing you should check instead since it's easier, is the fuse #6 in the under-hood power distribution box. See circuit diagram attached.

If the Shift Control module is getting 12V on the dark-green/light-green wire but not outputting on the yellow and orange, then I'd use a multimeter to measure the resistance the dash shift switch module should have in each switch position as shown on the diagram, that it should have between the white/light-blue wires and gray/red wires in each position (approximately): 3.9K, 1.1K, and 360 ohms.

If you wanted to test the shift motor directly, you could unplug the connector to the Shift Control Module, and apply 12V to the yellow and orange wires for a brief moment. Make one of the wires positive and the other negative then do the opposite, making the other wire positive and negative.

With the motor detached, note which position it is currently in first, then you should have it shift at least one way or the other if not both, then remember to shift it back to the position that the transfer case is in which you reported as being high mode right now.

This is perfect, thank you. I will update as soon as I go through these steps.

 

[CaseyMac]

**UPDATE**

So I still haven't been able to get under the X to test the connector to the shift motor but I did change out the relays that were behind the dash above the gas pedal. I don't know which one did it but now I can drive highway speeds and I no longer get the O/D light coming on or flashing. However, I do get both the 4WD HI and 4WD Low lights that flash, 6 flashes every 2 or 3 minutes. When I turn at slower speeds I do feel a pull so I believe my 4WD is just on all the time so I need to figure that one out. 4WD switch in the dash has power as well. But then again, everything I have read so far is that since I have the 98 XLT V6 with the 4WD Auto/Hi/Low it never truly does drive in 2WD. Correct me if I am wrong please. Still can't figure out why my speedometer, odometer, tripometer and temp gauge are not working. I have replaced the rear diff sensor and the transfer case speed input sensor, I've checked every fuse and relay under the hood and in the cab. Fuses are good and the fuse ports are all getting power. I have also checked it with 3 different clusters and all 3 do the exact same thing. And then for my previous PATs codes I was able to fix it based off of info I got from one of the admins (bad key gave me the code) so I cleared it and haven't used the other key. I have also ordered 2 OEM keys and I have the system Links cable with Forscan and can reprogram myself so soon as those arrive I will get that squared away.

 

[CaseyMac]

The motor only has two positions, high and low. If it is in high, that is the same position it would be in for 4hi/auto.

The motor does not ground through the case. Which high/low position it is in is achieved by reversing the polarity of the power wires going to it, making one positive power and the other ground to switch one way, and then reversing their polarity through the Shift Control Module to make it shift to the other high/low position.

Both of those wires are normally grounded, then the Shift Control module switches one or the other to 12V depending on which way it is supposed to shift.

It will only receive power for the moment it is changing position. You can check whether the Shift Control module is outputting this power. It's in the dash, behind the radio IIRC. The orange and yellow wires are the two which power the shift motor and reverse polarity.

You should also check the Shift Control Module's connector black wire, resistance to chassis ground, should be near 0 ohms, and there should always be 12V on the dark-green/light-green wire to it. If there is not 12V on that wire, or perhaps the first thing you should check instead since it's easier, is the fuse #6 in the under-hood power distribution box. See circuit diagram attached.

If the Shift Control module is getting 12V on the dark-green/light-green wire but not outputting on the yellow and orange, then I'd use a multimeter to measure the resistance the dash shift switch module should have in each switch position as shown on the diagram, that it should have between the white/light-blue wires and gray/red wires in each position (approximately): 3.9K, 1.1K, and 360 ohms.

If you wanted to test the shift motor directly, you could unplug the connector to the Shift Control Module, and apply 12V to the yellow and orange wires for a brief moment. Make one of the wires positive and the other negative then do the opposite, making the other wire positive and negative.

With the motor detached, note which position it is currently in first, then you should have it shift at least one way or the other if not both, then remember to shift it back to the position that the transfer case is in which you reported as being high mode right now.

Turns out I do have power going to the motor. Ended up using a different multimeter that had skinnier prongs on it. Apparently mine wasn't making contact for some reason. Anyways, according to the diagram you uploaded and your post, everything in the harness checked out and is good so it looks like the TC shift motor itself is what is bad. I connected it back together and did the brown wire mod adding a toggle switch on my dash so I can leave it in actual 2WD. I still have the flashing 4x4 HI/Low lights in that 6 flashes every couple of minutes pattern, but I no longer feel that pull when I turn. Once I can swap out the TC shift motor it should be good from there. Fingers crossed