I attempted a search and maybe I'm not using the right keywords but couldn't locate anything that seemed relevant.

Background, I have a small camper van built into a 1994 E-250.

It's fairly new to me and I had intermittent issues with the chassis battery (the van battery as opposed to the one for camping). I took the battery in to be tested and it was shot (which I had surmised as even disconnected it dropped like a rock). A couple of weeks and all seemed well and I popped out to it and the brand new battery was dead. i re-charged it and tested it over a period of days and it held a charge.

So, I figured something is draining it. I read about testing it with a test light hooked between the ground post and cable. Sure enough, when I plugged it in, bright light! I waited a bit to be sure it wasn't the Van circuitry humming to life. Nope, over a minute passed, still glowing brightly so I started pulling fuses.

I finally hit fuse #8, which lists a number of things including radio memory which was my first guess, but before I tore into the dash I looked at the other things, and it included dome light (could see it's off at least appears to be) and door locks. I pushed the power door lock slightly, not even enough that I heard the locks engage but the light got brighter. I pushed it a couple more times and then went out (I skipped saying that I had put the #8 fuse back in before this).

Now, I've jiggled the switch multiple times over and can't get a replay of the event, but I suspect it's what killed the first battery so can't imagine it's so easily 'fixed.'

Can anyone offer any clues as to where to start checking with the power locks? Switch? A Motor? Module somewhere? I'm not sure how to test further or even what is a 'most likely' culprit in this but am pretty sure I've found the system involved.

Thanks for any tips or leads!

Update - replayed the events to show my Dad and sure enough, it glowed to light again. This time out of a spirit of adventure, I played with the door lock button on a different door with the same effect. After clicking back and forth, the light went out. So unless both switches are bad, it sounds like an issue in between somewhere...

 

You have a good one here.
Until you can remove each door switch from the system individually, I suspect you may have a chaffed wire somewhere that is making partial contact , not enough to blow a fuse or open a breaker yet enough to draw down the battery.Some systems have a relay to carry the current required by the solenoids to make them operate.
I will check into what info I have available and will let you know what I find that may be of help in this case.

 

Appreciate any help!

The last thing I did this evening was open up the driver's side door as I figured sooner or later I was going to have to get to the switches. It was getting dark when I called it a night. I couldn't see how the switch is unplugged - it was like the wires and whatever connectors are on the ends must slide sideways into a notch on the switch - my little experience with this on a car I had to replace a dead switch was that the switch was just a switch on top of a big plug. This one looks more complicated - or at least did in the dark.

I'm sure you know way more than I do about this. A bad wire sounds like a bear to find. All I can tell at this point is that if I push the switch back and forth, eventually the test light sticks on. Then I can switch it another time or two and out it goes. With the idea that it could be a bad wire, I tried opening and closing doors to see if jarring it like that had the same reaction but never managed to get a glow that way, just triggering the switch (so far). BUT almost routinely, if I disconnect the test light and put it back on, it starts out on. I've had a couple of misses but more on than not.

Don't know if any of that helps or not! I'll take a better look at things in the daylight and maybe see if I can follow any of the wires back.

 

Ah, in the light of day, I could see how to remove the switch, it just plugs into the board but it looked like one piece in night. Not sure unplugging it helped me much other than I have identified that I appear to have the "reverse polarity" type of switch - 5 wires. If that's correct and the info. I found online is correct, that means I don't have relays, just the two power switches and the lock actuators in each door.

Later...

May have to give in and take somewhere. Getting very confusing. My book (the simple one that comes with the van) says that Fuse #8 is power locks. But they operate with the fuse out?! Removing this fuse is the one that initially showed the drop in power on the test light. And it's still the door lock switch operating that causes it to come and go. Don't understand then why the locks operate regardless if that fuse is in or not?

 

Sigh, scrap all of the above pretty much. I got an actual meter and hooked it up between the neg battery post and cable. Completely different results with it. Well, I think I can sort of explain it. When the light was acting as the bridge between those two points and I pushed the switch a few times, there was never enough juice crossing it for the doors to actually lock/unlock. With the meter, the doors locked and unlocked and the meter never 'stuck' on a higher amp level after. I think the behavior I was seeing was really connected to the locks just not getting enough power to do their thing. With the meter in place, it would naturally go up when I pushed to lock or unlock, but it would settle back to resting level each time without fail.

So, I revisited pulling every fuse under the dash with the meter in place. It never varied, but it's too high. .14 amps - I understand from reading this should be more like .03 but certainly under .05. Correct?

I even went out and pulled fuses in the power box under the hood. Same result, it stays at .14 amps.

I've read the voltage regulator in the alternator can be bad and cause this. If it came to replacing the alternator, that would (for me) probably be a job I'd take to a shop, but I would like to narrow it down if I can. Is there anyway to disconnect the alternator power without removing it? I can barely reach behind it and haven't been able to find anyway to see what's back there. The owner's manual refers to a fuse of some sort for the alternator with the starter relay. Is this an actual fuse somewhere I could pull?

 

I started to check some info for 94 E-250 and the Ford manual I have shows a 20 amp circuit breaker for the power door locks.
Next , you should not have over 50 milliamps "parasitic drain" at any time everything is off and all accessories are off. That translates to .05 amps if you are using the amp scale setting.
From what I have been able to gather so far, it sounds like your door switch assy is defective. To confirm this measure the amp draw across the fuse /breaker location for the power door locks with the switch connected and then disconnected. You should get no amp draw if the system is OK whether the switch is connected or disconnected. If you get a reading with it connected that would confirm the switch is making a partial contact when it should not.

 

I'm pretty sure the doors were a red herring because when I hooked them to the amp meter instead of test light, they locked and unlocked and the amps always went back down after. I couldn't replicate that issue with the amp meter so I'm pretty sure that was because the locks weren't getting enough juice through the light to completely engage.

But to be on the safe side, I did pull the power lock fuse (having located it, it's not what I thought it was originally, that's only if there's an anti--theft module). Anyway, when I put the test meter in place of the fuse and tried the locks, there was only amps registered when the button was pushed. It went back to zero immediately after, each try.

I have literally pulled every fuse, and it's always between .12 and 14 amps. I switched over to MA scale and it registered right around 112 milliamps. I have pulled every fuse under the dash and all in the power junction box under the hood and it never dropped below that.

I was able to pull one plug off the alternator, from what I gather is the voltage regulator, no difference in amps drawn from the battery. I don't think I can get to the larger wire on the back of the alternator without disconnecting the whole thing? I wish there was someway to disconnect the power to the alternator (without pulling it) so I could tell for sure if that's what's drawing from the battery...

At any rate, thanks so much for checking into the door locks info. I really think that turned out to be a dead end...

 

Okay, long story short, it turned out (with my Dad's help) not to be so hard to remove the alternator. As soon as I pulled the plugs and disconnected the one bolted on wire from the back, the 'mystery' drain went away. Connected back, there's the drain again. Rinse and repeat. I'd found plenty of mentions of "bad diodes" online and having ultimately pulled every fuse in the sucker to no avail, it seemed like it had to be in something that's always getting power like the alternator.

So, it was worth it to pull the alternator. Replaced and the drain appears to be gone. Knock wood!

So, if anyone else with this problem tries this, my recommendation is to test with the amp meter, not the test light despite finding plenty of people this worked for. For me, it just didn't work as well as an actual meter. And if you exhaust the fuses, go ahead and try the alternator, there seems to be plenty of people online with similar issues, you might be the next! Not a fun purchase, but the elation of not having to chase that drain further is good enough!

Thanks for all the help!

 

Congratulations you have just entered the automotive electrical twilight zone. The more you use it the better it , the meter, will serve you. good work