I have a 2003 E-350 Super Duty 12 Passenger Van, with F/R A/C, CD Player, etc. with a parasitic battery drain problem.

The alternator and battery both test good, so I hooked an ammeter on it to measure the battery drain by disconnecting the battery first.

Here are my results:

After the battery is disconnected, at initial connection of battery, there is a drain of about 1.2Amps, then it tapers down to .5 amp, then to .35amp. (The biggest drain is the interior lights which switch off after about 1 min.)

It seems to be hanging around .35amp and not dropping down to the .01amp which is 'normal' parasitic load for this vehicle.

At the .35 amp drain level, the battery will be half discharged in about 1 month unless it is charged. The problem is annoying but not dire serious.

I tried the following: disconnect the battery, leave it for 30 min to allow most of the capacitors and gadgets to discharge, and I was able to get it down to .1 amp after about 5 minutes at .35amp.

Somehow, I managed to reset it by leaving it disconnected for 30 minutes. I am afraid the issue will come back as soon as I am back on the road.

It seems to be that there is a circuit that is 'sticking' on.

Does anyone know which are the suspect circuits off hand? It has to be a circuit that is drawing about .35amps or about 3-4 watts. Not a light bulb, but something else. Suspects are: airbag, cruise control circuit (that I suspect is always on), seat belt, emergency fuel shutoff... ?????

Should I start pulling fuses until I isolate the defective circuit?

Anyone want to hazard a guess?


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The car is factory equipped with a system for putting most of the computers and gadgets in sleep mode once it determines that the car is parked and stopped for a period of time.

Except for a trailer brake controller (which I disconnected) there are no mods / conversion extras on this vehicle.

Previously, I suspected a sticking Cruise Control Disengage Switch - located on the Brake Master Cylinder. The way out is to stomp on the brakes a few times until the switch trips. This switch was previously replaced when it malfunctioned by sticking in the 'on' or 'release cruise control' position. It is the redesigned version of the switch that caused the F-150 fires. I suspect the replacement is also sticking / malfunctioning but not to the point of cruise control failure yet.

 

Ha! You're kidding right? Did your year have the fire-starter cruise control?

 

You should have no mre than .030 Amps or 30 milli amps..Try disconnecting the alternator a bad reg will do that.
If thats not it you will have to pull fuses...


Dick

 

The 2003 E-350 did not have the 'fire starter cruise control' switch, but it does have the redesigned switch that is common to the replacement for the F-150 fire starters.

Defective Alternator / Regulator --- That is a great suggestion. Thanks, I will try it if the problem persists.

Thanks everyone for helping.

 

If the problem comes back, set up your meter to monitor the drain. One at a time remove your fuses. When you find the one fuse that stops the drain look to see what is on that circuit.

 

^^ Exactly. Instead of speculating on what it could be and shooting in the dark your best bet is to start pulling fuses until you find the one that kills the drain.

What aftermarket add-ons do you have? Remote starter? Stereo?

 

Thanks again everyone ---

I have virtually no aftermarket add-ons. Trailer Brake Controller (Disconnected), Trailer wiring (Live, but no drain to plug), Wireless Backup Camera (Sender unit wired to side-marker light power, LCD to interior light that can be disconnected).

The van is pretty close to factory as you can get.

So the suspects have to be something that has an 'always on' circult and hopefully fused right from the factory.

 

Start pulling fuses...

You could have isolated the problem in less time than it took to post these messages!! I went through this after I came back from a business trip to find the battery in my Firebird dead. The switch in the console box fell out of its mount and the itsy-bitsy freaking light bulb stayed on and drained the battery over 2 weeks.

Seriously. The 15 minutes or so it takes to do it is much better than fretting about it.