Mystery battery drain

[Grabber5.0]

A few months before we bought a new primary vehicle, our 2000 Windstar LX developed a mysterious battery drain that I never had time to look into. Not that I have time now, but I want to track this thing down, and I'm hoping someone has some ideas of common culprits. I haven't started checking battery drain while pulling fuses yet. I only have a regular volt meter, but wondering if this would be a lot easier with the clamp-over style to measure current draw.

It will be fine for a while, then one day you get in and the battery is dead. During the time this was happening, the alternator died, so I thought maybe that was the problem the while time, but after a week or two, it happened again. The van has been sitting for a year, and I'm hoping it hasn't ruined the battery in that time.

Any advice is appreciated.

[rhandwor]

http://www.ebay.com/ search item 400756246262
First check interior lights. I've had a alternator voltage regulator go bad. They are built in on this year. I've found fuel pump relay sticking.
I usually set DVOM to milliamp setting disconect the ground and checked power flowing to ground pulling a fuse at a time.

[phil-l]

Another item to check: I found the brake lights stuck on when my '00 was parked a couple of times. It turns out that the the brake light switch (which is attached to the linkage above the brake pedal) can stick "on" when it gets old. Replace the switch; it isn't worth trying to repair.

[Grabber5.0]

Thanks for the tips. I'll try to get outside and check some things today.

That current tester looks interesting - any idea how it works?

[rhandwor]

Originally Posted by Grabber5.0

Thanks for the tips. I'll try to get outside and check some things today.

That current tester looks interesting - any idea how it works?

I think the tester measures the amps flowing through the fuse.

[phil-l]

Originally Posted by Grabber5.0

That current tester looks interesting - any idea how it works?

The "Amp Hound" tester can't measure currently directly - because it's designed to be used *without* removing the fuse, or otherwise being connected in series with the circuit.

Instead, it tries to accurately measure the voltage drop across the fuse (which is a very small drop), and calculate current flow from the voltage drop.

If you have an accurate voltmeter that can measure millivolt values, you can accomplish the same thing with that voltmeter. The "Amp Hound" essentially does the same thing, but does the math for you.

The below-referenced PDF shows you how to do it with an accurate (milli) voltmeter:

http://www.motor-talk.de/forum/aktio...hmentId=721311

[Grabber5.0]

Thanks. Been busy with Christmas and replacing the fuel pump in the F150, so I haven't had a chance to work on this yet. Hopefully I can get to it before I have to go back to work. I'd like to get the van back on the road so I don't have to drive the truck to work when I go in, plus my daughter needs something soon.

[Wayne10657]

My brother's 1997 Lincoln did the same thing. Battery ok for about a week then dead. Traced it to one of the power door looks. If I manually locked the door it could sit for over 2 weeks and be OK. Something to try.

[Grabber5.0]

Ya know, I did suspect the door locks at one time, but I had forgotten about it since we stopped driving it. Sometimes when I'd unlock the doors, one (or both, I can't remember now) or both rear doors would sometimes re-lock when you tried to open them. Also the hatch was starting to not want to unlock sometimes and I'd have to use the key. Thanks for the reminder. Was it a bad lock actuator?

[Wayne10657]

I was not given enough time to troubleshoot to that level. They needed the car so I just told them to lock it manually. I would love to know.