Electrical problems...

[dan brooks]

To start off with, I suck horribly at tracking down and diagnosing electrical problems - besides a total lack of patience, my color vision isn't very good (red/green color deficiency), so it's kinda hard to tell some of the wires apart.



I left my truck sitting at work since Sunday - been driving the department Cherokee for the week (hey, might as well save fuel costs when I can) - and the battery was deader than a $#!+ bug when I tried to leave today. Had to hook up jumper cables up to two cars to turn the Cummins over... one wouldn't even get the starter to click. :-laf



After driving across town (~45 minutes), I stopped at my friend's transmission shop. One of his guys started checking things out and there is a current draw with the ignition off - it's the circuit that controls the dome and cargo lights, and apparently the Chrysler EVS alarm system as well. Pulling the fuse stops the current draw, and when the fuse is replaced the alarm "chirps" and the electric door locks unlock. The wiring near the dome and cargo lights appears to be in good shape - no frays, burns, etc. After jumping the truck again - appears the battery is fried (nice sulfur smell when charging it, all but one of the cells bubbling) - I brought the truck home and disconnected all the plugs I could find for the alarm system, and everything else under the dash I could get to, but the current draw is still there.



I'm not sure how long the problem has been there - the truck normally doesn't sit for more than a day or two, which probably isn't long enough to drain the battery. When I went camping a few weeks ago, the truck sat for a little over three days and fired up fine, even thought it was cold enough to kick the grid heaters on. The camper battery may have helped "boost" the main battery a little, but it was pretty weak by then (wouldn't even fire the ignitor for the furnace), so it probably didn't do much - if anything - to help, so I kind of think this is a fairly recent issue.



So, seeing how I'm about worthless at diagnosing electrical problems, anyone have any suggestions on what may be wrong or where to go from here? I hate to pay someone to fix it - mainly because I can't afford to - so any help is greatly appreciated.

 

[CGauthier]

Hey Dan-those kinds of problems can be quite wacko to nail. Are you POSITIVE it's a current draw? How old is your battery? A weak battery can throw you for a real loopty loop if you know what I mean. It's apparent you already have one dead cell, but but because the others are bubbling that doesn't mean that they are completely up to par, there can be dead plates... I've went through quite a few batteries that wouldn't hold a charge very well and I basically ripped up the truck (not the Dodge tho) trying to find proof... almost every time it's been the battery(except the one time an alternator wire broke off it's connector). What I would do (not sayin it's right ) is if it's an old battery, I would change it and start from there because you probably need new anyways... jmho





Carl G

 

[dan brooks]

The battery is about 18 months old. The mechanic at my friend's shop was sure it was a current draw - he disconnected the negative terminal and hooked a test light between the battery and cable and the test light stayed on until he pulled the fuse.



I don't think there is any doubt the battery is bad - after driving it for 45 minutes it wouldn't even crank, and I've had it on charge for several hours and it still won't. I just can't figure out what is causing the current draw.



EDIT: Forgot to add, the charger is pulsing every few seconds. According to the manual that came with the charger, the pulsing means "The battery is connected to application that draws a small current (such as an interior light). "

 

[dan brooks]

Okay, did a little further "investigating" and noticed something: Besides the alarm apparently being affected by the #15 fuse, the radio and clock memory is on that circuit as well. Hmm... might have to disconnect the stereo and alarm and see if the current draw goes away.



I'm pretty sure the battery has taken a terminal dump - even with the battery alone hooked up to the charger it's pulsing. I'm hoping - seriously hoping - that it's just the battery and nothing more. Quick, somebody distract Mr. Murphy for the next day or two, I could really use a little good luck here.

 

[Paychk]

Dan



The FSM shows the #15 fuse as supplying juice to the following: underhood lamp, glove box lamp, radio electronics, map lamp, ignition switch lamp, dome lamp, cargo lamp, & power mirrors.

 

[CGauthier]

I didn't know these trucks came with alarm systems, wow-and I'm not sure how it works but do you figure the alarm is what could be doing it? I'm not sure but I think the alarm system would be drawing some current all the time, it wouldn't do you any good if the alarm only worked when you turn on the key... and a test light won't tell you how much current is going out-if it is the alarm tho it would take forever to drain your battery. Do you have a flashing light inside the cab? I don't know if you have them, but I wonder if those shock sensors need a little juice too. Other than that I cant see the cargo lights creating a draw without coming on, unless there's a short which should blow the fuse. I'm pointing at the battery, and I'd imagine the ole Cummins would exploit that sucker too-but hopefully if I'm wrong someone smart will chime in and help get ya fixed up



Cheers,



Carl G (not D, although i wish it was )

 

[dan brooks]

Alan - Thanks for the info. I have the FSM but didn't even check that part, instead just looked at the crappy little owner's manual to get the info - shows where my head is at today. I unplugged the underhood light when I was checking things out, but I'll have to see if the glove box light might be staying on... .



Carl - The alarm is one of the dealer-installed options. I was going to just pull it out completely to eliminate that from the list of possibilities, but apparently it required some swapping of wires in the plugs for the door locks, starter circuit, etc. , and I can't find the "old" wires anywhere, so that didn't work like I had hoped. The alarm has a flashing LED when armed, and a steady LED when disabled - the truck was parked in a secured lot so I left the system disabled, but even after five days an LED shouldn't have drained the battery.

 

[CGauthier]

Was the alarm disabled when you hooked up the test light? My test light is led too, and I'm sure if there's enough current to light one led there's enough to light two lol Led's take almost no current to light. I think your electrical system is fine bro, just not the battery. Do you have an ohmeter? They're cheap if you don't yet have one. I'm not sure how exactly to check how much current is being drawn, but I'll try to catch my dad before he goes to work tomorrow, he's an electrican for CP Rail , he's pretty good at that kind of thing.



Carl

 

[dan brooks]

Well, I disconnected the stereo and alarm and the current draw was still there as strong as ever. Then I realized the cargo light switch was on - turned it off and the draw went away, so I'm thinking the combined draw of the alarm and stereo is enough to light the test light (regular incandescant bulb, not LED). I have a digital volt/OHM meter but don't know enough to figure out how to measure the current draw.



If I can get the truck started tomorrow I'll take it down and get a second opinion, but I'm putting my money on the battery. Keeping the fingers crossed... .



Thanks for all the help!

 

[dan brooks]

Well, after leaving the battery charging all night it wouldn't start this morning, so I pulled the battery and took it to where I bought it. A quick check with the hydrometer confirmed the battery was DOA.



I tried measuring the current draw using my digital volt meter but it's apparently too low to register, so I don't think anything is wrong with the truck.



Thanks for all the help!

 

[CGauthier]

Crowd goes wild

Glad to hear it, now you can focus on other stuff like twin turbos and such





Carl G

 

[dan brooks]

Uh, I'll pass on the twins... right now I'll settle for a 4" exhaust and some tires.

 

[RGuzzo]

ohms law amps=volts divided by ohms or I=E/R I being current or ohms E being volts or electromotive force and R being resistance or ohms

 

[RGuzzo]

sorry I being current or amps

 

[dan brooks]

Why am I suddenly glad I didn't go into the electronics field - that was way over my head. :-laf

ohms law

Murphy's Law I'm familar with... .

 

[TKingsbury]

A couple of months ago, my truck did the same thing (sort of). Parked my truck in my driveway after work, next morning try to go to work and nothing. Put the charger on it and took the wifes car to work. When I got home it still wouldn't start. Put in a new group 31 and away we go. The previous owner had put in a smallish batt with only 650 CCA. No problems since.

Travis. .