Hi Guys. I have a ton of mechanical experience but very weak in electrical. I hate it. Bought a 1999 Cummins for my daughter that will be turning 16 in Sept ( she will be paying me back for the truck, lol ) and even with new batteries, if it sits for a week or more, the batteries drain to the point it will not start.

I have tried to research this problem & have eliminated the seat belt modules are not the problem. What else could it be ?

Any help would be much appreciated.



On a side not, it also does what I think is a weird thing. Sometimes when you turn the key to the on position, the wait to start light doesn't come on & no matter how long you crank, it will not fire. I know the ambient/engine temp sensor monitors this but if you turn key off & then back to on, the wait to start light usually comes on & once it goes off, it fires up right away. again even with engine warm, if the wait to start light doesn't come on even for 1 sec, you can crank to the cows come home & it will never fire up. Just thought I would throw that in here, incase it has something to do with battery drain ?

Other than that, everything else works as should.

Thanks

 

our trucks do not start until the wait to start light comes on. that is part of the computer programming is what I am aware of. My truck does the same thing batteries die after few days. I need to track it down also. the easiest way to track it down is to put a clamp on DC amp meter on the lines of the battery and can start by pulling fuses till you see the amp draw drop significantly. I was putting the meter on some of the small wires I add to the battery and was finding some amp draw and followed them and was able to reduce it some, but need to continue to test. for other amp draws. Ideally the amp draw should be at rest no more than 50-100 milliamps .050 amps. to about .100 amp. No pro just like you. if someone finds something I said as faulty chime in.

 

Glove box light?
Aftermarket radio installed with ignition on supply connected to battery supply?
The short wait to start light is showing the "boot" of the ECM. If it does not boot you try to type on a powered off computer.

 

Thanks guys. No aftermarket anything but a trailer brake controller. Will attempt to try using meter.

 

About using the meter-
exit vehicle, close all doors except hood, lock vehicle, ait for 15 minutes.
Put one wire of the amperemeter onto battery -, one on the battery - clamp.
Disconnect battery - while keeping both wires from the ammeter connected.
The readout should be very low- less than 50 mA. If higher, pull the fuses in the PDC (the fuse box under the hood) and watch the meter.
If there's a drop, note the fuse and report.
If no drop, repeat procedure, except keeping drivers door open and blocking the door switch in door closed position and pull fuses from the drivers side fuse panel in the dash. Again, check for drop in the draw, and record fuse designation.

Problems like that sound intimidating, but can be solved by following a diagnostic path.