It's been a while since I've been on the forum. I've owned my F250 for over five years now and haven't been able to enjoy it because of all the issues. I finally resolved the no start issue of the bad injectors but since then have always had a battery draw. I'm on the third set of batteries (new once again) and have only driven 7,000 miles since I bought the truck.

Okay the issue. I know how to check for a draw with an amp meter inline with the battery, make sure that the door latch is closed so the interior lights are off as well. Even with that done I have a 4.4 amp draw! I've gone through all the fuses, pulling each one out with not change. I've even disconnected all the solenoids to see if something under the hood was causing the draw. NOTHING!

I have a brand new alternator and also checked with it disconnected, no change. I have zero aftermarket electrical components hooked up. I even disconnected the brake control module and all the pillar gauges (they weren't working anyway).

Does anyone know of things that are constantly powered directly from the battery? I even pulled every relay under the hood with no change.

I'm stumped. I have a buyer lined up for the truck but can't in good conscience sell it this way without telling him about it or fixing it first.

Any suggestions are welcome. Please give me a hand!

Thanks once again, Kenneth

 

Disconnect the B+ from the Under Hood Battery Junction Box. Read the draw at the (-). If you have draw its on the B+ Side of the BJB. Somewhere the Battery Cables or Batteries have a path to ground or are not on Series.

If not, go back and check your work.

Do you have a Clamp for your DVOM?

Do you have a Fuse Buddy or similar Tool? They're no hard to make with a Fuse, Soldering Iron, Flux, and Solder.

PARASITIC DRAIN

Tools: Digital Volt Ohm Meter (DVOM)

Check for excessive battery drain or parasitic loads using an ammeter.

Make sure all electrical loads are off in the car, doors closed, and the key is out of the ignition switch.

Disconnect one of the battery cables from the battery, placing an ammeter in series between the battery post and cable clamp. The current draw reading should be less than 35 milliamps.

A reading higher than this (or manufacturer specifications) would indicate excessive battery drain. Something is "on", allowing current to flow running down the battery. Vehicles today typically will draw less than .020 amps (20 milliamps) of current to maintain electronic memories and circuits.

Note: If the battery is disconnected parasitic drains may temporarily increase. Circuits in the engine and body computers are activated and will run until internal timers run out. This reactivation period could be anywhere from a few seconds to almost 30 minutes. Whenever possible avoid disconnecting the battery while performing this test. It is possible to place one lead of the ammeter on the battery post and the other on the battery clamp, while at the same time lifting the battery clamp off the battery post. On side terminal batteries, connect the voltmeter with alligator clips and let sit until the timers run out.

Hope this helps,

Tom

 

What you really need with this is a fresh set of eyes. I have to go through this drill with RVs on occasion, just this morning in fact, and it can be crazy making. 4.4 is a pretty good amp draw, as you know. Did you also pull the fuses under the hood? I know how easy it is to assume I powered something down and then discovered I was mistaken.

Was this a problem before you did the injector work?

Steve

 

You mentioned the problem started when you did the injectors. Have you checked for a rubbing wire behind the 42-pin connector on the driver side? You can test that by unplugging the 42-pin connector.

If that doesn't fix it, then your tests would be more of the same - unplug something, check amperage, plug back in. You would want to first focus on the biggest connectors.

 

Okay, several questions Thomas, what is the B+ and BJB? I wish I had an clamp for my meter, no such luck though.

I also do not have a fuse buddy, in fact I'm not sure what that is either. I'll go look that one up.

I test with ONLY the meter in line between the disconnected negative battery terminal and the cable itself. This way I get a true reading and don't have any issues with shorting out my fluke meter. I always wait for around 30 minutes and don't open doors or ever put the key in the ignition. Right now the truck has been sitting over night and still has the same draw as it did yesterday during all my testing.

 

RV tech (Steve), I did end up pulling all the under hood fuses yesterday, I'll address that below. I wish I had a second set of eyes. Sadly I have no friends and don't know a single person in this area, let alone one that will wrench with me on my truck. Wish I did!

I mentioned that I noticed it when I did the injectors. Sadly I think this was an issue that the PO passed on to me. He was in a bit of a hurry to dump the truck. I thought it was just the no starting issue and the injectors but I'm sure it was this way before.

Tugly, what 42 pin connector are you talking about?

 

B+: Battery Positive
BJB: Battery Junction Box (Under hood on your vehicle, next to Master Cylinder).

Fuse Buddy is a Brand Name. Makes it easier when checking amperage draw or drop across a circuit with low current amp clamp.

 

Here is the update of what I did yesterday: I spent over 8 hours working on the truck tracing wires and disconnecting everything!

I found out that if I have the under hood mini #7, maxi #14, 22 and 28 disconnected I only draw .82 amps...almost withing range according to Ford. If I plug in any of these four, doesn't matter which one, it jumps to 4.4 amp draw again. I unplugged the computer, GEM, interior radio, brake switch, fuse block (entirely out of the truck), seat wiring on drivers side, throttle connector, trailer brake module, cluster, and headlight switch, along with anything else I could unplug on the drivers side under and around the column. The draw stays the same!

I also found that if I jump the post of the battery power directly to the under hood fuse block to ground that I get the same 4.4 amp reading. This makes me think that somehow a power wire is completely grounded out. The problem with that is there should be a fuse blown, unless it is an unprotected circuit. Am I wrong in this thinking? Remember I did this testing through the negative side of my battery so as to not spike and kill my expensive meter.

What am I missing? Do I need to completely remove the dash, pull out all the wires and split the loom? Is there anyone that knows of a circuit that isn't through the fuse blocks?

There are no auto electric places in the area around St. Louis where I live now. If anyone on here lives close by or knows someone that might be able to help, please let me know.

 

Thomas, I wondered if you were talking about the battery positive, sorry my brain just isn't thinking today I guess. I don't have a battery buddy but you're right, that would be easy enough to make. I just don't have a clamp for my meter to use one with though.

 

Tugly, I re-read your post. If you are referring to the connector that is on top of the drivers side above the engine cover then yes I have done that. I've disconnected everything I can get to on the engine. I also pulled the fuseable link off the solenoid to make sure I could figure it out in the system. That didn't change anything as far as the draw goes.

 

22 is the culprit, it feeds the under dash distribution panel. So, focusing on #22 and removing the fuses under the dash one by one until the draw drops is next. Once you identify the field circuit, there is the issue... Well somewhere in their. Post back with the circuit or fuse number and I'll pull some wiring diagrams.

 

Thomas, with the entire interior fuse block pulled out of the system the draw is still there. I started with the interior fuses and none of them made any difference in the draw. That's why I pulled the entire thing out. Any other ideas?

 

The only things in the cab which I can recall are not controlled by the under dash fuse block is the Fuel Pump Relay behind the Radio and Mixer Door on the HVAC.

 

I'll have to see about digging into the fuel pump relay then. I didn't know it was back there. That's at least a starting point.

Thanks!

 

Your short is ahead of the interior fuse block. You know that because powering any of the four fuses you noted in your under hood block is as good any other one. The only way that can happen is if they are run to a common bundle or grounded block. In theory what you found shouldn't happen as it negates the reason we have fuses which is to protect wiring in individual runs. What you found is any fuse is as good as any other for this draw.

Since you removed the interior fuse block, you have taken that out of equation with no effect and there is no unprotected circuit. You have a feedback loop which is tying those four fuses together somehow. Did you by chance reference your owners manual and see what they are supposed to protect? That might give a hint.

In the one I just completed yesterday, I had a 5.5 amp draw which was taking place through a failing normally open relay that was partially shorted.

I would not split the loom as I don't think it will do more than confuse a confusing situation. What is causing this problem is very basic. Finding it is Hell!!

Steve