Guys:

I am looking for some direction on diagnosing power door lock issues. My door locks will only unlock manually. Meaning nothing happens when pressing the FOB or the door lock switches. Sometimes the switches in some of the doors will unlock the doors. Nothing seems to work to lock except manual. BUT, I have an intermittent issue where the doors will mysteriously lock, unlock, or lock and then unlock, while driving. It doesn't seem to happen often, it doesn't seem to be specific to rain or hitting a bump.

I am looking for some help on how to diagnose this issue to find the problem. If any of you have encountered this situation and can offer a check list for me to run down, that would be great. I think I saw some threads on this in the past, but usually it was specific to the door lock mechanism not working. As mine seem to lock and unlock under power from some source, it seems to me that my problem lies elsewhere. I am thinking it is a ground issue, but do not know where to start in my search (of the vehicle).

Thanks.

 

1. Check your grounds. Don't look at them. Take them apart. While you are there, clean them up (shiny metal), give a dab of dielectric grease, and put them back together.
2. Check the wiring bundle where it goes between the frame and the door. These wires are asked to flex every time the door is opened or closed, and they can break inside the insulation. A meter may show good continuity, but they may not be good. Use a test light.

 

Is this '99 E350 equipped with factory Remote Keyless Entry or an aftermarket kit installed by who knows who?

If factory along with checking the wiring primarily between the drivers door master switch and the RKE module located on the driver's side wall just behind the driver's seat. Its possible that device itself is beginning to fail---something not uncommon for any vehicle that age.

At this point its a 50/50 shot this is related to the physical wiring you can access. That being said I'd pay close attention to the control on the driver's door---there's a lot of connections there that could cause your symptoms.

 

That's good general advice. Are you talking only about the grounds in the doors? Grounds to the door locks themselves? Most of my electrical car work in the last few years has been on older FIATS, where there are ground "flowers" that have a bunch of grounds leads connected to them. Those are easy to find and to clean, if poorly located. I'm not sure where all the ground points are on this van, though.

As for the wiring through the door, again I agree that is a good point to look and I will do that (I had a bunch of things come up after my prior post). The question is, why would that cause an intermittent lock/unlock scenario, but not cause a situation where I could intermittently lock/unlock with the key fob or door lock switches?

Have patience with me. It's 105-115F out these days and I typically only have sporadic opportunity to work on this car, and right now I had bigger problems to sort out (I just had to replace all the heater and coolant hoses and the oil cooler and now I'm chasing a misfire at idle and low power immediately off idle).

Thanks for your help.

 

It's a factory system. This is an XLT club wagon. This is starting to sound like a pull all the seats and panels to diagnose and fix problem. Which means I may have to wait until the weather cools down and/or I can find a garage to work indoors in and a backup car to drive while I sort the problems out. Thanks for the info.

 

The TSM for my '98 goes down the line as follows;
A2 Check fuse function panel fuse 4. Mine had built up crud on the ends of the fuse. Lacking replacement fuses I wire brushed fuse nos. 3,4 and 5 and after reinsertion, the RKE still isn't working properly, but all the dome lights now work.
A3 Check circuit 54 (LG/Y) for voltage at LH power door lock. I think I'm having to remove the inner door trim to acess the connector C500. I went out to the wrecking yard today and while there were no RKE equipped vans I practiced removing the door panel and once removing the quarter trim on the A pillar (snap fit) after removing 4 trim retaining screws the door panel slides up and out. Then I'm guessing one has to cut the vapor barrier to gain acess to this connector.

 

So, today I had a bit of time. I pulled the switch gear out of the door and ran a tester to ground. I checked the leads. The LG/Y has power and I was able to test the switch by putting a tester to each side of the pink/striped leads coming out of the lock switch. When the switch is activated in the correct direction, there is power to the lead. So that eliminates the switch and also confirms that I have power out to the switch. I did the same thing on the front door on the passenger side with the same result. I also checked fuses 4 and 5 and both tested fine, as did Fuse 16 under the hood (all three have something to do with the power locks).

I haven't been able to check the wiring through the rubber insulator that runs between the door and the body because I cannot get it out of the way. Is there a trick that doesn't involve cutting it? It is in good shape, pliable with no tears.

As for grounds, it would help to have some type of diagram that shows where various grounds are on this vehicle.

Also, right now none of the switches or the FOB will lock or unlock the doors. If I press the lock button on the FOB long enough the horn will sound. That's it.

If I am to pull the panels and get to the RKE, then I'm going to have to acquire some panel tools because I about shredded my hands attempting to get the hard and sharp plastic surround for the passenger barn door window off so that I could get the door card off and remove and repair the cable ends on the door handles so that the door would operate again.

 

Had the same problem...turned out to be the lock/unlock switch it the back door...disconnected it and all is well

 

I FOUND THE FIX !!!

...at least on mine. I did a front brake job recently and the dome lights stayed on draining the battery. After charging the RKE started working. I intentionally made mine fail today and, while at work I disconnected the battery. Upon reconnecting the RKE started working again. So, in conclusion as no RKE modules seem to be available I'm going to rig a switch to cut power to my RKE module to force a reset.