Engine/Transmission (1998.5 - 2002) Killing Batteries in 3 days?????

[Drue]

My truck is killing the batteries in my '99' in 3 days if I leave it parked. I have been unable to trace any shorts from the fuses.



I can remove the smaller wire feeding the under hood fuse block and check it with an ohm meter to ground. I have checked each and every fuse and relay and can not understand what is draining my system. The alternator seems fine with no reaction on the ohm meter. When the truck is running after I recharge the bats, everything seems normal. It seems to take about 3 days to drain bats to low to light up the dome lights inside. The weird thing is that it will not do it every time the truck is parked. But it is getting too frequent to ignore and regular enough to be traced.



I need help!#@$%! When I leave the fuse panel feed wire disconnected, the bats stay up fine, making me think the starter if fine.



'99' LWB, 4x4, SLT, regular cab, 53 block w/ no crack!

 

[JLandry]

Drue,



I wonder if it could be one of the relays sticking in the closed position in the PDC (Power Distribution Center) under the hood? I'm not sure a sticking relay could cause this problem... I would have to study the wiring charts to be sure... but you might try pulling all the relays just to see if the batteries hold their charge.



I'll try to take a look at the wiring charts and let you know what I find out.



Best regards,



John L.

 

[Drue]

I am thinking it must be something like you suggest because it will not do it every time I park the truck, but it is getting more frequent. When I use my ohm meter, I can check between ground and the main power wire (disconnected from batteries)going to the main power distribution center and my meter will go to 0. When it does this, and I pull each relay and fuse out with no change in the meter. I have even done the same process with the fuses inside the cab. I am still puzzled. To me, this indicates the electrical drain is going through the PDC and not through a fuse or relay that I can remove.



I have even thought about trying my infrared temp gage to see if the relay sticking would be warmer that others, but here in Florida, the daily temps are reaching into the 90's already, so I doubt I could discern enough difference.



What ever the drain is, I think it would be equivalent to leaving the dome lights or parking lights on for three days. But I already checked that no lights are actually on at night, including the under hood light, and the glove box lights.



Any insights or suggestions to try are very much appreciated.

Drue

 

[DPellegrin]

DRUE- Does your multimeter have a built-in current shunt? If it does, then connect it in series (one path to ground) with either the B+ battery cable or the ground cable so that any current going into the truck will have to pass through the meter. This will give you an indication of how much current is being drawn off the batteries. Then begin disconnecting relays etc. and see when the current drops off. If you do not have a built-in shunt then connect a test light in the same manner so that any current going to the truck has to pass trough the filament of the light's bulb. The start disconnecting things that you believe to be using current. The test light will go out when you find the culprit.



Regards,

 

[JLandry]

Does your multimeter have a built-in current shunt?

Drue,



I was just going to suggest the same thing that DPellegrin did. Using an Ohmmeter the way you've been doing really isn't the best way to isolate a current drain like you have. The Ohmmeter function is best for testing the continuity (open or closed) of a circuit.



To isolate the drain, disconnect the auxiliary battery, then as DPelligrin suggested, connect the current measuring function of your multimeter in line with the main battery circuit or use a cheap 12v test light (available at any auto parts store). Pull one fuse and relay at a time until the current flow measured by the multimeter changes, or if using a test lamp, the brightness of the bulb changes. Make a note of which fuse(s) or relay(s) cause a change and report back here. If needed, we'll be able to suggest added steps to figure out how to solve the problem.



The fact that you have an intermittent problem could make things difficult, but not impossible. Ideally you want to conduct these tests when you know the battery is being run down.



Please keep us posted.



Best regards,



John L.

 

[Drue]

Thanks for all of the input.



My multimeter does not have the built-in current shunt that I know of. I do have a test light that I will go try this evening. Then I will report back... .



Thanks again for your thoughts,

Drue

 

[Drue]

OK, here's what I have found. A digital amp meter connected between battery (+) and PCM reading 0. 36-0. 37 amps. I have pulled each and every fuse or relay that I can. Most have no change in the reading. However, the following was observed:

"50 AMP BATTERY" pulled, reading drops to 0. 17 amp... . so ~0. 20 amp draw

"20 AMP POWER OUTLET" pulled, reading now 0. 06 amp..... so ~0. 11 amp draw



I was able to replace each and return to the starting value of 0. 36-0. 37 amp. I was able to replace each independently and confirm the approximate draw.



Then I went to the inside fuse panel by the drivers door and was able to pull Fuse number 1, 15A PARK LMP and drop the reading from 0. 06 to 0. 00 amp.



I realize that some circuits have a small draw even if the truck is off(radio presets. . etc), but are these readings within reason or is my truck not in the draining mode any longer? (Intermittent problem)????



With all of that being said, where do I go from here? It seems as though I might be narrowing it down to something I don't understand.



Again, many thanks for your help and insights so far.

Drue

 

[DennyDay]

Just for grins and giggles, check the starter motor for drain in the starter switch. On a '99 could be some oil got in there and is causing a mild short. Withe the engine cold (overnight) feel with your hand for a warm spot, especially on the relay.



Denny

 

[Mad Bomber]

Are your batterys maybe shorting out (plates inside)

 

[Drue]

I have checked the starter motor and 0. 00 amp draw. I have checked the smaller wire tapped onto the battery terminal and 0. 00 amp draw. I have checked the wire feeding from the alternator and 0. 00 amp draw.



I can disconnect the power feed to the PDC and the batteries hold their charge every time. I have even tried to reconnect the PDC and it will kill the batteries in about 3 days. I have thought of the batteries internal fault and had them load tested, they checked fine. Both batteries are only about 3 months old, matching group 27.



What is a normal amp draw for the PDC with everything normal?



Thanks for all of the input and thoughts,

Drue

 

[Nick H]

I had the same problem and mine turned out to be a bad glove box light switch that would not press down all the way so the light would stay on all the time. I disconnected the switch and the problem went away.

 

[JLandry]

Then I went to the inside fuse panel by the drivers door and was able to pull Fuse number 1, 15A PARK LMP and drop the reading from 0. 06 to 0. 00 amp.

Drue,



I'm checking the wiring diagrams for possible causes and will post what I find soon...



John L.

 

[JLandry]

With all of that being said, where do I go from here? It seems as though I might be narrowing it down to something I don't understand.

Keep narrowing it down...

"20 AMP POWER OUTLET" pulled, reading now 0. 06 amp..... so ~0. 11 amp draw

Due to the size of the current draw and the circumstances (described below), I think this could be your main culprit right here.



This fuse is connected directly to the auxiliary power outlet in the cab (looks like a spare cigar lighter) and is on all the time (not routed through the ignition key). If there's a current draw here, something must either be plugged into the auxiliary power outlet which uses power (like a cell phone charger, GPS receiver, etc. ) or someone might have tapped into the supply wire in order to power some after market accessories... like maybe an alarm system, a CB radio, or a stereo amplifier?



You might leave this fuse out for awhile and see if the batteries stay charged and to see if you notice any after market accessories which stop working.



The bottom line: A stock truck should have no current flow on that fuse with nothing plugged into the auxiliary power outlet!

"Fuse number 1, 15A PARK LMP and drop the reading from 0. 06 to 0. 00 amp.

That's a pretty minuscule current draw... I don't think it's the problem by itself.



Please keep us posted,



John L.

 

[DennyDay]

Dru - - - There was a problem with the

main feed from the battery to the PCM - I think it ammounter to a loose connector that was killin' batteries in short order - - had the problem on my

'99 but can't remember how we fixed it. Check search on forum or maybe someone will have a better memory than I have.



Denny

 

[Drue]

I have checked everything I can think of and everything everyone has suggested. I have recharged the batteries and reconnected all fuses and relays. I will see if it will still discharge in 3 days.

Thanks for the help,
Drue

 

[hcole]

Drue, I have seen similar problems like you describe before. It turned out to be plugs, bulb sockets and even once a starter having water that corroded things and would temporarily dry out and be OK until it got wet from rain, washing, or running through water. You might check your current readings right after a rain or washing. This can be difficult to find. Good luck.

 

[Drue]

I wish something like this were possible, but we have not had rain here in weeks. The weather radar has shown rain over us, but it never made it to ground. This truck has not been driven in rain in several months now.....

I am beginning to suspect a switch some where that is going bad, I just need to prove which one. .

Thanks for your input,
Drue

 

[JLandry]

I am beginning to suspect a switch some where that is going bad, I just need to prove which one.

Drue,



You mentioned you've recharged the batteries and are waiting to see what happens. Besides the current testing you did, have you done anything different to the truck this time... like remove the fuse for the auxiliary power outlet?



Or are you trying to establish a baseline with the current drain you measured?



John L.

 

[HPetrat]

Drue,



Unplug your underhood light for a while and see if ther is a difference after a week/3days.

My 98 did the very same thing and after a month of testing all of the electrics, I simply unplugged the underhood light and it cured the problem (duff mercury switch in the end).



HP

 

[K5IP]

Drue,

You have had many good posts which should help.

However, killing batteries in three days rpresents a signifigant drain. Probably much higher than the load you have measured. In fact, If you have two good batteries, they should be able to provide about 65Amp hours each for a for about 130 amp hours of drain.

(Three days at 1AH is 72AH of load) and is a much higher load than you have measured so one of thre possibilities exist.

1. you are not charging your batteries fully. (or they are old and do not have full capacity)

2 The batteries have inernal leakage. (remove battery connections and see if conditions continue without

any load)

3. I just do not understand the situatuon. (but keep trying, sooner or later I will)

Rog