1995 L400 draining battery

[Rural]

I've got a 1995 L400 that draines the battery to the point that it can't drive the starter motor after a few days of sitting. The battery is three years old. Perhaps the problem is a short or sticky switch (ie. door closed switches) somewhere in the electrical. The door open light flickers and sometimes sticks on while driving (and all doors are closed). Rarely, it would stay on while parked, so I pulled the bulbs for the cabin lights. This problem started late last winter and is intermittent. There was a run over the summer where it was fine, which is why I didn't explore it further. Also, I was driving the van on a daily basis so the battery never drained enough that I noticed that problem.

I'm about to replace the battery as it is probably ruined, but I'd like to track down the short before doing so. Trouble is, I'm not an electrician, and could use some general strategies. Obviously, I can unplug the battery and measure resistance across the van's positive and negative lead. But I'm thinking that I can test at the fuse boxes to figure out what line is the problem.

My guess is that it's the back door "latched" switch, but I can't really be sure.

I can operate a volt-meter and dabble in electronics, but this sort of thing is well outside of my comfort zone. Any suggestions would be welcome.

[VanVonVan]

I just had a door latch latch problem appear. It was intermittent before but last week it was stuck on. I found out it was the back hatch, so I tried getting in there and seeing what was the problem, it was a bit of a pain but I found out the sensor for the back was shorting itself out and making it seem like the door was open. I disconnected the sensor and it seems to have bandaided the problem for now. All my power locks still work as it is on a different switch. I am going to fully fix it in the spring as here in winterpeg we are hitting the -40s and I don't feel like ripping a door apart.
Russell

[izack98]

Here's a good way to check to see whats causing the drain.
Disconnect the negative battery terminal from the battery, then connect a voltmeter - one lead to the negative terminal on the battery, one lead to the (still unplugged) negative battery cable. If something is drawing power your voltmeter will show you voltage. Sometimes it wont always show a full 12 volts, it depends what's drawing.
If it shows a draw, you can narrow down the source of the draw by pulling fuses. Ensure your doors are closed - no key in the ignition etc. It helps to have someone watch the meter for changes while you play with the fuses. Once you pull the fuse which powers the thing(s) that is drawing power, the voltmeter will drop, or go to zero.
From this you can narrow down what is causing the issue. Most fuses power several things. You will need to find out what's on that circuit, plug the fuse back in, then unplug the things on that circuit separately until you read zero.
Or if you have a suspect, start by unplugging that item first and see if you have a drop.
This won't always work as some things draw continuously (clock). But you should get an idea once you begin pulling fuses as to whats powered and what's not. If you read zero at the beginning, try opening a door, or turn on the headlights and see that you have an increase in voltage.
I haven't tried this on my Delica so I'm not sure if there is anything that draws constantly. But from what you are describing, it sounds like something is.

Clear as mud?

Most battery suppliers will test your battery for you free of charge.

[Rural]

Thanks fellows.

VanVonVan, we might be in touch about how to access the door latch switch, but I'll start with izack's procedure. In fact, that's really close to something I just found on Youtube:

[Rural]

So I looked for a parasitic load and couldn't find anything. I couldn't get anything to register on my meter's 10A unfused circuit. So I went back inside and set up a simple circuit with my children's set of Snap Circuits (which are a lot of fun for dad's too). Still couldn't get anything to register on the 10A circuit, but the 400 milli-amp unfused circuit worked fine. I even tried another super-cheap meter and got the same result (10A didn't work, 400 milli-amp worked). Went back outside and tried the 400 milli-amp on the L400. Got a couple of milliamps load. Strange.

Just checked again and I couldn't get any load at all... At least, not on the milliamps scale.

Hmmm.... Maybe it is the rear gate latch switch and it doesn't happen to be stuck, or it is something else that doesn't happen to be in its problem-causing state.

In any case, to rule out the battery being the issue, I've disconnected it. I'll know more in a few days...or not.

[izack98]

Oops, I forgot to mention to set the multimeter to DC amps. But I see you figured that out.
Maybe it is your battery after all. Any warranty on it?

[Big-Bird]

The clock in the dash draws a small amount of power as do digital stereos so that you don't lose your time or radio station presets.

Take your Deli to a local PartsSource and have them do a charging system test. Its free and will tell you if a battery is weak and or if the alternator is putting out enough amps which will also affect battery life.

[Rural]

Big-Bird, we're a ways from a PartsSource, but the next time I'm in a major center I'll give that a try. Thanks for the suggestion.

Izack98, the battery is out of warranty. It's Energizer brand, bought from Wal-Mart. If the battery is the problem, this is the first issue I've had with that brand.

With all the holiday festivities, and the website being down last night, I haven't followed up on this or done much fiddling. I've just left the battery unplugged and have been checking the voltage each morning. Over the first night, from a fairly charged state of 12.6V, it dropped to 12.5V. Today, two days later, 12.3V. Charging to 12.6V is just barely acceptable for a battery, but I'm not sure how much one should expect the voltage to drop over time.

I did reread izack98's first post without replacing voltage with amperage :) and decided to have a look at voltage. With the negative terminal disconnected from the battery, the voltage from the negative battery terminal to the negative connector is exactly what it is from the negative to the positive battery terminals. That confused me as I was expecting the circuit to be open. So I stopped suspecting the battery (although 12.6 V charged is right on the edge of being too low). Now that I've slept on it a couple of times, the voltage reading makes perfect sense, as there are small loads (stereo and such) that would pull the voltage up. My feeling is that the problem is the battery and may go shopping today.

Sound sensible?

[kitesurfer]

FYI, I had this happen and replaced my battery and even installed a manual switch between the battery and the alternator in case it was a bad diode in the alternator allowing power leakage. In the end I replaced the alternator and that fixed the issue, which tells me that in my case, the alternator was just not recharging the battery as much as you'd expect, not that the battery was draining unexpectedly.