I have an '02 Dodge 2500 and in the past few weeks it's been hard to start or won't start at all w/o a jump. After doing a few checks and some internet research, I decided that I either had a bad ground or a parasitic drain somewhere.
Yesterday I checked all of the grounds and started systematically checking for a drain w/ my multi-tester hooked in between the driver's side negative battery post and cable. Initially, I had a reading of almost 400mA but that eventually went down to 263mA and stayed constant. I checked all of the big stuff first: alternator, stater, Edge box - and eventually went on to the fuse box in the engine compartment. I got a constant 263mA the whole time.

I then checked the fuse box inside the cab (w/ the door switch wedged closed) and the when I pulled the I.O.D. fuse my reading went down to 7mA. A few of the other fuses would reduce the draw by 1-2 mA.

So I'm pretty confident that the drain is in the IOD somewhere. My question is where should I start looking?
I have a Haynes manual and a service manual .pdf for an '01 and have been trying to study the wiring diagrams as best I can.
From what I understand, there are a whole lot of things that are tied into that circuit - are there any common culprits?

Any advice and/or suggestions would be greatly appreciated.
Thanks.

 

check the seat belt switch I have seen problems with them keeping the module from powering down



The seat belt switch is designed to control a path to ground for the seat belt switch sense input of the Electro-Mechanical Instrument Cluster (EMIC). When the driver side seat belt tip-half is inserted in the seat belt buckle, the switch opens the path to ground; and, when the driver side seat belt tip-half is removed from the seat belt buckle, the switch closes the ground path. The switch is actuated by the latch mechanism within the seat belt buckle. The EMIC monitors the driver seat belt switch status, then controls the seatbelt indicator and sends hard wired chime requests to the Central Timer Module (CTM) based upon that input.

The seat belt switch receives ground through its pigtail wire connection to the body wire harness from another take out of the body wire harness. An eyelet terminal connector on that ground take out is secured under a nut to a ground stud on the left lower B-pillar (standard cab models) or the left lower cowl side inner panel (club cab and quad cab models). The seat belt switch is connected in series between ground and the seat belt switch sense input of the EMIC.

 

The seat belt switch is a small, normally closed, single pole, single throw, leaf contact, momentary switch. Only one seat belt switch is installed in the vehicle, and it is integral to the buckle of the driver seat belt buckle-half, located near the inboard side of the driver side front seating position. The seat belt switch is connected to the vehicle electrical system through a two-wire pigtail wire and connector on the seat belt buckle-half, which is connected to a wire harness connector and take out of the body wire harness.

The seat belt switch cannot be adjusted or repaired and, if faulty or damaged, the entire driver seat belt buckle-half unit must be replaced.

 

Disconnect and isolate the battery negative cable. Disconnect the body wire harness connector for the seat belt switch from the seat belt switch pigtail wire connector located near the floor panel under the driver side front seat cushion. Check for continuity between the seat belt switch sense circuit and the ground circuit cavities in the seat belt switch pigtail wire connector. There should be continuity with the driver side seat belt tip-half and buckle-half unfastened, and no continuity with tip-half and buckle-half fastened. If not OK, replace the faulty driver side seat belt buckle-half unit.

 

Cav circuit function
1 z2 20bk/lg ground
2 g10 22lg/rd (heated seats) seat belt switch sense
2 g10 20lg/rd (manual non-heated seats) seat belt switch sense

 

According to the shop manual:

"When testing a diesel engine-equipped vehicle with dual batteries, do not check the IOD between batteries. One battery may be at a higher state-of-charge than the other, which will cause a high IOD between the batteries. Remove the negative cable from the passenger side battery negative terminal post prior to performing the IOD diagnosis."

The IOD current should be less than 25 mA.

When you measure the current on the negative connection of the driver's side battery, was the passenger's side battery disconnected? It should be.

The best way to test the seat belt timer module for a fault current draining your battery as BigIron 70 suggests is to roll down the driver's side window and close all doors. If you reach in the window to the seat belt and try to pull it out it will, but after about 20 minutes it will not because the seat belt timer will have turned off. This also stops the battery drain.

Having to jump-start the truck because of a low battery problem makes me believe the batteries may be bad. Try a charge to get them fully up before blaming something else. Weak batteries will self-discharge quickly.

 

Thanks for the replies.

Bent Valves:
I did the drain check w/ the passenger's side battery disconnected.

Also, both batteries are brand new - purchased Wednesday....



BigIron70:
Thanks for the info. I'll check out the switch in the morning.

 

So I finally got around to testing the seat belt switch - work has been super busy and the weather is nice enough to ride my motorcycle...


I get no continuity when I tested the seat belt pigtail - with the seatbelt fastened or unfastened.

If I were to make a "jumper" so that there was continuity in the pigtail connector, then shouldn't my 263mA drain go away? If so, how long would it take for the system to shut down?

Thanks for all of the help so far...