New guy needing some help. Truck is a 99 24 valve/6 speed 3500 dually. Batteries won't hold a charge. Cables are new (with soldered ends), batteries are a year old, heater grid relay is new (but heater grid is currently dis-connected), no radio, seat belt module dis-connected. 275k miles, alternator looks original, but still puts out 14.1volts (measured with meter) at idle.


After sitting 3 days, batteries show 12.47volts. Took both negative cables loose, and used a meter between cable and negative post on battery. Got a little spark, meter read .03, but if you wiggle and scratch it you can see it jump up to .43, but I can't get that all the time. Cables spark when re-connecting.


I've heard something in the alternator can sometimes drain a battery. (Forgive me, I'm a painter, not a mechanic). Should I have the alternator bench tested or is something else going on? Only electrical add on is an Edge ecd 2000 box.


Any help would be great. I only use this truck once a week to haul water for my cistern, so it sits quite a bit, but needs to work when I need it to.


Gregg

 

I don't know if this applies to your truck but I had one with a light in the glove box and the switch was bad the light stayed on and drained the batteries. Took me awhile to figure it out.

 

Look up videos on how to check for a parasitic drain. That may help you find the problem.

 

Welcome to the site.

That glove box light used to be a main cause of battery drain, check that and for parasitic draw, too as mentioned...

 

Read this and make sure your seat belt module isn't causing it.

https://www.dieseltruckresource.com/...2500-a-300106/

 

Seat belt module is already unplugged, not that. Got in it this week and batteries were down to 12.13 volts.


Got another thing to check. It might be the Edge box. Last week, I had it basically turned off. This week, I shut the truck off with it on the first "light". Batteries were drained more this week than last.


Gonna do some more testing and totally unplug the box while it sits this week.

 

i think you have a bad battery, one bad battery will drag the other down,

 

Ok, new update. Even with the batteries at 12.13 volts, fired right up. Hauled 3 loads of water, 4 miles to the water plant and 4 miles home. Parked the truck and checked the voltage. 12.75 volts. Decided to do another amperage drain check. Took both negative cables loose and used my voltmeter between the cable and battery post. Like before, got a little spark and readings would go high for a split second and then show .03. Unplugged the Edge box and checked again, same readings.


I had already checked all the circuits in the dash fuse panel, but not the ones under the hood. Turns out the 40 amp "Trailer Wiring" fuse was the culprit. Pulled it and got 0 amperage readings and no spark re-connecting the cables. Looked at my trailer plug and it has definetly seen better days. Haven't towed anything for a long time, so I haven't looked at the plug. Out of sight, out of mind, I guess.


Checked the voltage today, 12.58 volts. Will continue to check as the week goes by.


Thanks for everyone's help, Gregg