Howdy all, this is essentially an update to "Fuse 12" postings. I have seen many vids on hooking up a test light/meter inline on both poles. On the negative there is no light.
On the positive I get light only on the cable to the fuse box. If both cables are connected, no light. With a meter, I start pulling fuses, and get a .55 drop on the fuel system fuse.
this seems to be normal.Putting fuse back in and meter reads full 12v. All other fuses do not show a drop. Battery still dies overnight. Using a jumper, it starts right up and there are no warning lights on the dash. Runs great.
OBDII tool shows three faults. O2 sensor, HCI sensor, and EVAP.
While checking wiring under truck along frame, I checked the EVAP and the two lines were attached, so I pull the nipple off, and it is corroded all over with a big hole on top.Will replace that! All grounds I could find are clean and good.
When I first had the issue, pulling fuse 12 did keep battery from going down, but now has no effect. Took out radio, g-box light, lighter, 2nd DC connector in dash, unplugged everything in left door panel-Elect. mirrors, windows, and lock. Pulling this fuse showed no voltage drop on meter.
"Professionals" three, to be exact, could not find anything. Why isn't there a device that will simply test the entire electrical sys. and pinpoint the fault!!!!! Arrrggghh!
I am here live now, and will wait for any responses. There are two things I love, my Dodge Truck, and my Guitar. guitar works fine.

 

How much draw are you getting (amps) with everything shut off?

Disconnect the negative cable at the battery, put your meter on the highest amp reading it has, red lead goes to battery, black lead to cable. Start pulling fuses in the PDC. See where you get the biggest amp drop. Don't forget the fuse block in the cab either.

 

Also could be a bad diode in the alternator, Does it charge like normal? It will still put out but a bit less if it has a bad diode. Put your meter leads on the battery and see what voltage you have, Then remove the alternator fuse and see if the voltage changes.

 

There is a device for that, I got one free and they are about $1200 new. Where are you located at (which state) if you are close to me I'll come to you with my device and we can figure it out.

 

you can do the exact same test HeyYou suggested with a test light also if you don't have a multi meter or experience running one. the light will go out once whatever is causing your power drain is stopped. i know i used a test light to figure out my subwoofer amp in my 1 vehicle was draining the battery.

 

I never thought of a test light, good call!!

 

Howdy. I did check on voltage drops with a meter, and only the fuel sys. fuse showed a drop of .55v This is the max of a normal .2v-.5v drop. No other fuse showed a drop.
I do not suspect the fuel pump, I replaced it two yrs. ago. I will further test out the alternator as Moparite said. I will get meter leads with clamps for a better connection.
I gave the truck a good run around town to charge battery. Held until next day and started fine at 10am. By 4pm, still juice to start. This morning, not enough.
Pulling the 20a fuse in the PCM will take out the dash fuse box, and isolate the engine area. I think.
Still need to find the dual nipple for the EVAP canister, my Haynes manual does not give part #s. And no images match my unit! As LLBB vehicle, Chrysler took it back from the first owner and factory re-built it as a 2000. So, 98-2000 info in manual does not jive with whats on the truck. I have contacted Chrysler about this and hope they respond.
I have had this truck for 18 yrs. and the worst was a blown head gasket, and I tore it all down and fixed it 2 yrs, ago.
I am beginning to wonder if the PCM is at fault. Thanks for all the advice.

 

Found! the real culprit was the shell wiring. inside light box had melted wires. Also licence plate light holders were corroded. Removed all slaved wiring.
Alt. has a funny reading, which may be diodes going bad. Battery still has a slight drain, but does not die overnight. Holds 12v and will start. Idle not holding until rev for a minute. Then it becomes normal. Going to do Alt. checks again. Progress!