1998 E350 Chateau passenger van. Power door locks only seem to work with the switches when it's raining. If you use either door lock/unlock switch while the vehicle is running (and during a period when the locks aren't working) it activates the dome lights for a short period. Don't know if the vehicle has RKE or not (I just picked it up and there were no remotes, but it's a "Chateau" so I would think it would).

 

Checked the power at all the switches yesterday, all 3 do have power. The locks also started working while I was doing this. The locks stopped working when I shut the rear right door and no amount of persuasion would get them to work again (all three switches are still getting power and pass power to the proper terminal when depressed).

 

Just brainstorming and thinking out loud... maybe it will help trigger something for you:

Sounds like a bad ground or broken ground wire. Water could be acting as the temporary conductor to make the ground connection. Shutting the right rear door causing locks to stop working might indicate a broken wire in the door loom (but I wouldn't think it would be a single ground circuit through that wire). Maybe there's a ground in that area that the vibration opened the circuit?

 

Swapped out all the switches today (since I have two E350s that was easy). No joy. If an actuator is bad can that prevent all of them from working?

 

I don't think so... my rear actuator doesn't work intermittently, but doesn't affect any of the other actuators.

I have the factory wiring schematic, but it's nearly impossible to read (to the point of being useless). I'll try to take a look over the weekend to see if there's anything obvious that stands out.

 

Wondering if all the switches/actuators share a common ground? I see power at the switches and the locks still don't work.

 

Pulled the connections from the RKE today, nothing changed. No lock/unlock at all. Power is still present at the switches. I'm wondering if all of the actuators are bad, may swap one of them out to see if that changes anything.

 

You've got some bad grounds, Ford supplies 12v to the high side of the loads and the switch provides the ground that completes the circuit. The grounds are carried in the wiring harness to where ever Ford decided a central ground should exist. You might try removing one door panel and provide a ground path for that lock solenoid to the chassis. If that door lock operates it confirms the bad ground suspicion. The wire colors used on a '94 lock solenoid would be Light Green w/ yellow tracer (12v) and Black w/ white tracer for ground. I'm guessing your '98 would be the same. Your jumper will connect the Black w/tracer at the solenoid to some exposed sheet metal, preferably under the dash. (You don't want rusty door hinges to play tricks on us)

 

The location of that central ground is what I need to find. Since they invert polarity I would think it would have to be through some relay.

 

For what it's worth it shows 12v on the switch connecting the meter only to the terminals on the switch (not going to a known good ground, grounding through the harness).