2000 F350 - electrical short, killing battery

[crewgrl]

2000 Ford F350 Superduty 7.3 l powerstroke turbo diesel, 2 batteries.

The battery was very low when I tried to start it on Saturday morning. Was in a hurry, so threw the booster on, waited 10 minutes and it started ok (but the windshield wipers made 1 sweep when it started, I'm _sure_ I didn't hit the wiper switch).

Same story this morning. Checked both batteries. Undid one one battery, and undid the negative battery cable on the other battery, when taking it off the post or putting it back on, getting a noticeable spark, with the ignition key off. Something is drawing power from the battery when the key is off and I am not finding it.

Pulled each and every fuse individually, checked battery draw each time. Checked lights, switches, accessories such as stereo and remote starter.

Ideas and suggestions welcomed.

[Tallavana]

there are a few things in the truck that do draw current even when the truck is off. Such as the clock and anything you may have plugged into the lighter. They draw enough to make a spark. If the terminals arent clean the carbon build up burning off may make a bigger spark. As for the wipers, I dont know. I would suggest have your alternater checked first as well as the batteries. That would help rule out the obvious before you put a lot of time into searching for a problem.

[jbdawson]

Be sure that one battery is not shorted internally and killing the other one. That is a common occurrence on dual battery Ford diesels. I had it occur twice in my '91.

[fxdwg]

Connect a test light between a battery terminal and the cable. Disconnect the other battery. The light should light because of the short. Start pulling fuses until it goes out. Usually the clock and radio/computer memories aren't enough draw to light the test light. When you're pulling fuses from the inside box, tape the door light switch so the interior lights are off. Since the wipers are triggering, I'd look closely at the steering column. Probably a chafed wire there.

[boatycall]

Do you have an aftermarket alarm?

[crewgrl]

Thanks all for your suggestions so far.

After I posted, I refined my search terms and found 2 excellent posts on this topic :

Re: Electrical problem, batteries goin dead?? [Re: patchzx7r]
#2782324 - 02/08/06 05:36 PM by SteveRacer

Re: Electrical problem, batteries goin dead?? [Re: SteveRacer]
#2783258 - 02/09/06 11:53 by sootthrower

Anyway, no alarm system (that I know of - truck was purchased used in 2004), and the problem seems to have cleared up - for now . . .

Now that you mention it, I am suspicious of the column - had to replace the overdrive switch a few months back. Will post again if I find out for sure what it is.