I have a 98 Mountaineer V8 AWD... The other day the power door lock on the drivers door quit working, even with the remote it wont lock the doors. If I press the other door lock buttons, the one in the rear and the other on the passenger side door, all the doors will lock. I have tried to chase down the wire ( pink with Yellow stripe, or green stripe, I forget which one it is now ) I don't have a wiring diagram to know where the wire goes. I have even swapped the door lock buttons from side to side and it still didn't change anything... Is there something that is a common problem with these that I need to know about??? does anyone have a wiring diagram of the doors?? There is no power going to the drivers door lock, but there is to passenger door. I am thinking of running a jumper wire from door to door and see if this will fix it, but I would like to find the problem and fix it instead of cobbing it.... Any help would be appreciated

 

Is it the door lock itself that doesn't work, or the door lock switch? You mention if you press the other door lock buttons, all doors will lock. Does that include the driver's door? If you press the lock switch on the driver's door, do any doors lock?

There is a common issue that could cause the switch to not work. Wires between the door and the cabin tend to break inside the insulation, often in the driver's door due to its more frequent use. Sometimes the speaker wires will break first, sometimes the power mirrors, sometimes the power windows, and sometimes the power locks.

I can provide you with the wiring diagram if you send me a private message with the request and your e-mail address.

-Rod

 

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I just replaced my door lock actuator for the drivers door. Was still sticking as I replaced the mechanism as well.

 

The door will lock when I use the other switches. The drivers door lock switch wont lock any of the doors. I know the actuator works because its locking and unlocking with the other switches. If the wire had a break in it at the door then it wouldn't work with the other lock switches right??
The door will lock and unlock, but only if I push the other switches... But, the drivers door switch will unlock the door, it just wont lock it, or any of the doors. Its only the locking part of the switch that quit working..

 

Not the case. The lock switches work by providing a ground to the lock and unlock relays depending on which way the switch is pushed. The switches do not reverse polarity. Also, the switches are wired in parallel, so if one of the wires were broke between the driver's door switch and the relay, the other switches would continue to work as would the door lock actuator. Since your driver's door switch does not work to lock any of the doors, the wire that is probably broken will be the pink with light green tracer wire.

You could test this by using a test light, connecting the clip to a known good ground, then removing the switch assembly from the door and touching the tip of the test light to the pink/light green wire at the switch. If the doors do not lock, you know this wire is not getting a good ground back to the relays. You could then open up the wiring bundle as close to the cabin as possible, find the same pink/light green wire, and piece the insulation with the test light tip. If it now locks all doors, you know the break in the circuit is between that point and the switch assembly. If the doors do lock when you touch the test light tip to the pink/light green wire at the switch, then you know the switch assembly is the problem.

-Rod

 

I have done this in a few spots. At the switch and in the wiring harness under the threshold plate under the driver side door, and it still doesn't work. But if I press the lock on the passenger side door they ALL work, even the drivers door will lock....

 

Yes, based on the wiring diagram, this makes sense, and a broken pink/light green wire to the driver's lock switch would explain it. Maybe the break is not in the typical location between the driver's door and the cabin.

To confirm your test light has low enough resistance to enable the locks, try touching it to the pink/yellow wire at the switch to see if the locks attempt to unlock. If they do, then hopefully you have a multimeter that you can use to test for continuity between the lock switch's black wire and the pink/light green wire when the button is pressed and held for "Lock". No continuity = bad switch. Continuity = a break in the circuit between the switch and the lock relay.

-Rod

 

I have even taken the switch from the passenger side door and put it in the drivers door and it still didn't work.... Here is something even more bazaar, When I press the last two buttons on the key less entry on the door everything locked ( thats the way there all setup).... So from the door to the rest of the switches it still works, just not with the switch its self and the push button ( the after market push button is spliced into the drivers door lock wire).. Are the switch's not interchangeable from door to door?? It plugged right in. I didn't pay attention if all the studs from the r/f door switch match up into the l/f door switch.... I just know when I swapped them from side to side, I still had the same problem and to me that ruled out the switch..

 

I don't understand the comment, "When I press the last two buttons on the key less entry on the door everything locked ( thats the way there all setup)." Also, are you saying there is an aftermarket remote keyless entry system installed? If so, where does it tap in to the wiring?

-Rod

 

The key less entry buttons on the outside of the drivers side door, when you press the last two buttons, all the doors will lock. All I'm saying there is, that part is still working and all the Fords are setup that if you press the last two buttons on the outside door pad, all the doors will lock. Yes, it has an aftermarket remote starter that also locks and unlocks the door. The wire from that, to lock the doors is spliced into the wire behind the drivers side kick panel. So, in short,,, when I press the door lock button on the door, it WONT lock any of the doors, but, when I press the last two buttons on the outside of the door on the key less entry pad, it WILL lock all the doors. But,,,, if I press the lock button on the aftermarket remote starter, it also WONT lock the doors. AND, if I lock the doors with the factory remote, it WILL lock the doors.....
Let me ask this, are the lock switches from the driver and passenger door NOT interchangeable?? Because when I swapped them from side to side, I still had the same problem, so to me that ruled out that the switch was bad. Hope this all makes better sense now. I don't know how else to explain it all...

 

The remote entry keypad in the driver's door does not connect to the lock and unlock wires in the driver's door, those lines go to the RAP module, then activate the lock and unlock relays. If the aftermarket remote start works to lock and unlock the doors, it tells me the broken wire is, again, between the driver's power lock switch and either the lock relay or where the aftermarket remote starter is spliced in to the circuit. The relays are located in Auxiliary Relay Box #2.

Where are the "few places" that you checked with the test light to see if the locks would activate, and did any of them work?

Since the master door lock/window switch assembly has a large connector (C501) versus the small connector for the passenger lock switch (C614), it's not intuitively obvious if the switches are interchangeable. From looking at layout of the connection locations, it would appear the physical pin layout is slightly different. However, if the switches connected just fine, they probably are interchangeable. Did you try connecting the switch from the driver's door to the passenger door to see if the switch worked everything there, or did you only try the passenger switch on the driver's side?

-Rod

 

The aftermarket remote wont lock the doors, it will just unlock them. The same problem I'm having with the switch. I did put the switch from the drivers door in the passenger side and it worked everything just fine. So to me, that ruled out that the switch was bad. I tested the wire on the switch plug and on both sides of were the after market remote is spliced,( behind the driver side kick panel ) and got nothing. when I tested the unlock side with the test light, it unlocked the doors. I was gone all weekend and I haven't had a chance to take it back apart again and look for the problem. I am trying to cover all the bases so when I do take this apart again I have several things to check. I don't want to have to do it a third time..

 

With that additional information, it confirms for me that the problem is between where the aftermarket system is spliced in to the lock wire and the lock relay. You need to keep tracing that wire until you find the break. If your test light has a good enough tip to pierce the insulation, that will speed things along. Just be aware that if the wire could be exposed to moisture where you pierce it, you will want to cover the small hole with either some tape or RTV, etc. to keep moisture from getting to the copper wire.

-Rod

 

I finally was able to work on my Merc. I traced the problem to somewhere under the back seat.. So I ran a jumper wire from under the back seat where I could get the locks to lock, to the drivers side kick panel. All is good now... Thanks for all your help Shorod