Hello all,

I'm currently tracting down a battery drain on my 93 Ford F150 Supercab 4.9L that completely drains the battery in 4-5 days when the truck sits and have run into a brick wall. With the alternator pulled from the system, I've traced the drain down to one of the large plugs going through the firewall. As you stand at the drivers side, it is the 2nd (Largest) plug from the Driver Side fender well. I disconnected the plug and used a shorting wire to go pin to pin until I found the pin with the current drain. The suspect wire/pin is colored blk/org and is located on the outsite row on the left side of the plug (1st contact on the bottom left just under where the plug mounting bolt is). I don't see any pin numbers on the plug or the jack. I can find numerous references to blk/org in chiltons, but can't figure out exactly which one I'm looking for. I've disconnected the headlights switch and the module behind the glovebox, disconnected door dome light switches, pulled all fuses from both interior and engine compartment fuse blocks, etc. If I could find out where this blk/org wire feeds to, I'm sure I could get it fixed. If anyone is familiar with the plug and wire that I'm talking about, I sure would appreciate the help.

BTW, I'm testing the current drain by disconnecting the neg battery terminal and placing the ampmeter (fluke digital) in between the battery and the cable.

If the truck is run every day, it has no problems - if it sits longer than 4 days the battery goes completely dead.

Thanks in advanced - if more information is needed, I'll do my best.

Matt

 

You will have avoltage draw of 12 volts, but check to see how much of an ampereange draw that is there. It should be a low draw as it feeds current to the memory in your radio. You may also hae a bad battery.

 

Battery is new. Radio is removed - so no current draw there. Has to be a fairly large draw to completely kill a battery in 4 days. As far as DC Amps, I'm seeing at 5.89 draw on the meter. With the suspect cable removed, draw is 0 amps.

 

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I think he wants you to change forums to an "electronic" one.

=*(
trying to tear appart our fragile community.


I thought that on the other side of the firewall, where the plug comes through you could reach above the pedals to find it.

If you got current coming through it, you can find it with the volt meter by grounding to the chassie.


I dont see my haynes around to check it out right now.

Sounds like you have a bad ground someplace draining the battery.

 

You're right, found that it was #70 on that plug and blk/org on the interior side as well. Appears to go to the fuse #13 with a tap off to fuse #9. Hayne's schematics are a bit lacking, so it may go elsewhere as well. With both fuses pulled, still see the current drain. Ran out of daylight last night so I'll get back to it today after work.

p.s.) I appologize if this is the incorrect forum for this post, just figured since it zeroed in on the year of my truck that I'd have a better chance finding someone familiar with it since I was asking year/model specific questions. I didn't see a way, as there is with other forums, to move the thread as a user. Possibly there is an admin tool to accomplish that.

 

I used to work on BMWs back in the late 80s and we would see problems like this all the time. We would use a test light between the negative batt cable and neg bat post. If the light came on, it would indicate a draw. We would pull the fuses 1 at a time to isolate the draw. 99% of the time it was a bad antenna motor or glove box light that would not switch off. It sounds like you are on the right track in tracing your problem. Have you tried pulling the fuses 1 at at time to isolate the drain? Do you have any aftermarket electronics, alarm, stereo etc? Have you tried jiggling the ignition switch, beating on the dash, slamming the doors, wiggling the wiring harness, etc. to see if the draw would stop?

I am very new to the ford truck world, so my advice might be a little off. Keep us updated of what you find.

 

if you slammed the doors on many of these 10+ year old trucks you would get rust all over the place!

my dash creaks enough and i go out of my way to beat on it!

another common short that drains battery is the cigarette lighter or power point having a loose wire that grounds out the circuit. many jeeps have this problem.

 

The diagrams that I have don't seem to tell much about the wiring leading to and from that 72 pin connector. But if the suspect wire feeds fuses 9 and 13, there a few things you might want to do.

Fuse L in the distribution box under the hood feeds fuses 5, 9 and 13 in the inside-cab fuse box probably through the wire you located. I would pull fuse L and measure the current. Measuring the current drain with your fluke digital ammeter between the battery and the cable is a good method - just make sure that your under-hood light (if installed) is not lighted when the hood is raised.

If current drain changes at all with fuse L pulled, I'd reconnect the battery to the cable and measure current across the terminals fuse L plugs into.

For information, fuse 5 feeds the air bag system, fuse 9 feeds the power point, and 13 feeds stop/hazard lights, anti-lock module, part of cruise control, anti-lock brakes, and automatic transmission interlock.

A 6 amp draw at 12 volts should generate 70 watts of heat. You might be able to find the problem by feeling for components that are warm (hot!) when they should be cold.

There are some real experts in the electrical forum who might be some real help in locating this problem.

Lou Braun

 

Thanks for the input. I was thinking if a short was responsible for the draw, the amperage would be enough to make the problem wire evident, if not smoldering, so I was mainly concentrating on components that might be active when they shouldn't be. Pulling the fuses one by one has no bearing on the draw at all, after it cools off outside a bit I'll try to pull groups of fuses, such as the 5, 9, 13 at the same time. As far as the other ideas, I've disconnected the alternator, power point, cigarette lighter and the glovebox light, along with all dome/courtesy light plugs, light switch, the main harness feeding the multi-function switch in the steering column, the radio, removed all wiring from any after-market device, and unplugged every plug I can get to without completely pulling the dash out. I'll keep at it and post my findings to the forum. Thanks for the input all.