Serious battery drain, 1999 2500

My 1999 2500, 110,000 miles, has a bad battery drain.
Takes about two days to go dead from a full charge.

Battery new last Aug. Alternator seems to charge it up. Once it's driven it starts fine. But when it sits a few days, it's flat dead.

No lights are on. The interior override is pushed. Hood light is removed.

check sun visors light may be on

If checking lights doesn't work. Unhook the battery ground and put a dvom between the battery terminal and the ground wire. Watch for excessive amperage pulled after the underdash lights go out. Pull one fuse at a time until you find the circuit causing the problem. Then disconnect one item in the circuit at a time until the problem is found. The alternator could have a ground. A fuel pump relay can stick.

I blieve the 99's still have the voltage regulator in the alternator, I would disconnect negative battery cable and use a voltmeter to se how much drain you have and then disconnect the wire from the alternator and see if you still have a drain, if not you know where your problem is. If still have drain I would start pulling fuses to pinpoint where the drain is.

Hope this helps

Thanks for the suggestions.
Checked the visors. Seem to be fine. Off when closed.

I'll try the alternator disconnect and fuse pulls next.

It doesn't have to be digital the analog unit will work fine. Set it to pick up amps. You are checking for amperage not volts.

Removed each fuse from the inside panel and from the under hood panel.
Checked meter reading after each pull.
Meter set on 250mA. Pegged all the way, off the meter, with two exceptions.

#19 "Radio Batt". Very high, just under 250, but still in the readable range.

and

The large fuse on the under hood panel marked "Battery".
Removing it brought the the needle down to about 25.

Disconnected the battery lead to the alternator as well, with no change.

You need to get a Haynes manual with a an electrical diagram. Check what this 40amp fuse supplies and disconnect one at a time.
Try pulling the fuel pump relay and check what this does. Next pull the eec relay and check what this does. You could have a bad ignition switch.

I pulled all those relays too. Meter was still pegged. Truck was supposed to have had an ignition switch change just before I picked it up. I'll call the shop that did the work and confirm.

The Fuse is a 50amp "protected circuit".
Owners manual lists the circuits protected as "Battery, Fuse Block Busbar"

I did a search of the forum and found this from 777stickman: "So looking at the wiring diagram in the manual, it shows the 50a Battery fuse powering 3 wires to the instrument panel fuse block. One wire goes to the fuse 1 (STOP-HAZ). Another goes to Fuse 2 (T CASE). The 3rd goes to a PWR ACCY circuit breaker which I don't have a clue what that is."

I will check if I have a manual tomorrow.

Any suggestions would be greatly appreciated. I plan on picking up a manual at some point.

I'm starting to wonder if the PWR ACCY in question is fuse #19. It's listed as "Radio, BATT", and "BATT" is what the 50amp is listed as. The meter was actually quite inconsistent when #19 fuse was pulled. First check, the meter read about 248. I checked a few more times see if I had good contact and it dropped to 25. Checked several more times to make sure it was constant. Just when I thought it was the bad circuit, it jumped back up to 248.

I'll look at it more carefully tomorrow.

Various computers will draw current intermittently. If it has a security system, opening a door (even with the dome override on) can cause the ~250 mA draw for up to 20 minutes.

Have you checked the "case draw"? Put one lead of your voltmeter on a battery terminal, and the other right next to the other terminal, but on the plastic case. The electrolyte can leak out out the battery and form a very thin layer that conducts a small amount of electricity. If it reaches from one terminal to the other, it can cause a marginal battery to fail in a few days. If you have any voltage at all, clean the battery with a mixture of baking soda and water. Rinse it with pure water when done.

Yes, it does have a Clifford.
Pulled the fuses on it to remove it from the equation.

Any suggestions would be greatly appreciated. I plan on picking up a manual at some point.

I'm starting to wonder if the PWR ACCY in question is fuse #19. It's listed as "Radio, BATT", and "BATT" is what the 50amp is listed as. The meter was actually quite inconsistent when #19 fuse was pulled. First check, the meter read about 248. I checked a few more times see if I had good contact and it dropped to 25. Checked several more times to make sure it was constant. Just when I thought it was the bad circuit, it jumped back up to 248.

I'll look at it more carefully tomorrow.

No, fuse #19 is not the "PWR ACC" circuit breaker. This C/B powers the Keyless Entry Module, Power Door Locks & 6-Way Power Seat. How to change it or check it out I don't know.

Fuse #19 gets its power from the "LIGHTING" fuse #8 in the Underhood Fuse Center.

Another thing is that this info is for '99 and older (old body style).

I couldn't find a diagram. I think your readings are from interior lights which turn on for a short time when shutting of the key. Pull that fuse and check the other fuses for bleed.

Another thing is that this info is for '99 and older (old body style).

That is what I have. Thanks for the info on that third wire though .

I couldn't find a diagram. I think your readings are from interior lights which turn on for a short time when shutting of the key. Pull that fuse and check the other fuses for bleed.

They're off. Looks like a jumper between the cable and battery needs to be in place for 20 to 30 minutes to give computers time to cycle prior to performing the fuse pull test. I hadn't allowed enough time when I tested the circuits earlier.

I bought a new battery. I'll install it tomorrow and retest. The right way this time.

So far so good with the new battery.

Thanks for all the help.

Happy meal: How did you solve the problem. I'm having the same drain through the 50a batt fuse. Thanks, MP Wood