gorms

I've been having issues with a drain on the batteries with the key off for some time now. I haven't really looked into it until lately, because it takes about a week of sitting before noticing a weaker start. Batteries are less than one year old, and it drains them down to almost nothing after about a month.

Anyhow, I think I remember my old 1500 as having the seatbelts locked with the key off. The seatbelts in the 2500 are always unlocked, but they do work. Any ideas as to what controls them? Maybe a stuck relay or something? I checked everything obvious, including the Haynes diagrams, with no results. I have not amprobed the load with key off, but I imagine just the solenoids would be enough to drain the batteries in time.

Thanks for any help.

RickCJ

Yes seatbelts are locked with key off, open door and insert key sends power to unlock. There is a 20 min timer under the console and BCM behind the ash tray.

infidel

There have been several people here with the same sort of problem caused by a bad timer module but I don't think it's your problem.
If you read your owners manual you'll find it says the engine must be started long enough to charge the batteries at least every 21 days.

gorms

Personally I don't care if the manual says it needs to be started every day to charge. I have one 1000cca bat and one 850, they should hold up longer than a month without charging. I understand the computer draws some, but I see a pretty good arc when I disconnect the battery cables and tap them to the posts. Also hear seatbelts click at the same time. And I know that they stay unlocked all the time, just didn't think of them being electronic. Thanks for the help, I'll check the module.

bcbigfoot

Have you did the lockup switch mod (mystery switch) I recently had battery draw issue's as well, traced it back to the jumper wire in the fuse box that is used in conjunction with the lockup switch mod.. It had a .5 amp draw going through the jumper, it would drain the batteries right down in about 3 weeks. I havn't heard anyone one else with this problem maybe this is a issolated case.

VICIOUS FISHER

Have you tried pulling the IOD fuse,there is a shipping/storage fuse in the panel on side of dash it looks like airbag fuse, with similar guard/cover. It is my understanding that they are provided so that you can pull it halfway without the fuse falling out and the battery won't drain while vehicle is shipped to dealer. Fuse #12 IOD fuse. I don't know if this is related to your problem but thought I'd bring it up

BigIron70

Also make sure glove box light is not staying on when glove box is closed.

NO: 08-35-97
SUBJECT: Dead Battery From Ignition Off Draw (IOD)
DATE: Sep. 26, 1997
SYMPTOM/CONDITION:
Battery goes dead due to the glove box lamp remaining illuminated when the glove box door is closed.

torquefan

After you shut off the truck and close the doors, the seatbelt module takes 20 minutes to time out and power down. You need to disconnect one battery and install an ammeter in series with the other to confirm this. If you disconnect power and reconnect it, yes, you will see an arc because you are waking up the module (and every other module) and causing them all to draw power. Put the ammeter inline and walk away for half an hour. After this period, the modules will all be timed out and total system draw should be 30 milliamps or under.

I should also add that any time you open a door, the door ajar signal wakes up that module and unlocks the belts. That's why they always seem to be unlocked. Try shutting your truck off and leaving it for a half hour, all locked up but with one window rolled down. When you come back, reach in through the open window, without opening a door, and give the seatbelt a tug. It should be locked.

gorms

Well thanks for giving a few other things to look for. I've narrowed it down to the seatbelts because last winter the truck was garaged for a few months while I rebuilt the tranny. Windows were down the entire time and the seatbelts were always loose. I didn't really think much of it until the batteries were so low that the seatbelts were clicking

SIXSLUG

My trucks seatbelts do not lock in place. I have had it sitting for over a day in the shop with the windows down and when reaching thru to test the belts they uncoil like they always do.

My batteries do not go down even after sitting for up to two weeks in the winter.

What is this feature for anyway?

The ammeter test suggested is the best route to take when diagnosing an electrical problem.

Kurt

torquefan

Because of the rear doors on a quad cab, the seatbelt retractors couldn't be installed on the 'B' pillar area as they would hamper access to the rear seat. They decided to install the retractors in the seatbacks, and could not use the traditional pendulum style retractor that uses inertia to lock up, as different people recline their seatback to different positions while driving, and the pendulum would be erratic. They made the retractor electronically controlled, with a module to sense deceleration and solenoids to lock the belt when the module decides they need to lock.
Generally it's a good system and I haven't seen a lot of trouble with it.

SIXSLUG

Why are the belts supposed to lock in the retracted position when the truck is shut off and no one in the seat?

Kurt

RickCJ

The first quad cabs had what was known as the SCTM or seatbelt control timer module under the middle of the front seat. This box controls the solenoids in the seatbelt retractors during a collision or rollover. Its a little black box that senses G-loading, angle of roll, and time. Any angle greater than 45 will cause the belts to lock up. Any G-load greater than acceptable will lock them up. Plus when the ignition is off, it will lock up the belts to prevent the solenoids from drawing their normal 0.5A current...which will kill your batteries in about 2 days if its not working. When you open the doors the next time you get in, the SCTM senses this and unlocks them before you even get in the truck.

This box was necessary because the Quad Cab seats had the retractors in the seat and the conventional pendulum was useless in a collision if the seat was reclined too far. As the seat was reclined...so was the pendulum. So Dodge installed these boxes and solenoids to assist the mechanical lockup mechanism at times when it couldn't work.

There is a way to test your seat belt system via disabling the SCTM box and checking your wiring to the solenoids. Sit in the truck with the key in the ign. Close the doors. Push in the cigar lighter...cycle the key on-off 3 times leaving it on after the third cycle (do it quick...not slow). Within a few seconds after this...unplug the lighter...and the seatbelt guy will light up on the dash constantly letting you know its in test mode. I think both belts will be locked up at this time. Open each door and the belt on that side should unlock...or vice versa...I cant remember which way it works. This test mode only lasts a couple minutes so be quick. It tests that the ign power to the module is correct...the door jamb ground switches are communicating with the SCTM, and that the solenoids are operating properly and all the wiring is working. Key off the ign to end the test and the guy light will go out.

You should remove and reinstall the IOD fuse before performing the test. This resets the SCTM. The IOD fuse is the constant on power source (pink wire) to the SCTM. Another test is to roll your windows down...shut the truck off and go away. 30 minutes later or so you should be able to come back to the truck...without opening the doors...and reach through the window. The belts should be locked up and not pull out. This tests the timer function of the module to cut the constant on power to the SCTM.

There is a light green wire that goes from the SCTM module to the Air Bag Control Module. Its a "dumb" communication link to the ABCM that tells it the SCTM is working and in place. It sends a 3V signal to the ABCM. If this signal is bad or out of range...the ABCM will light the dash warning guy light signalling a bad seat belt system.

You can also check the solenoids in the seats by unlugging them under the seat and seeing if you get 50-60 ohms across the terminals of the plug. Thats the normal reading.

The simple solution may be to replace the SCTM black box for $95.00. THey sometimes fail for no apparent reason. It could also be a faulty ABCM...which ultimately controls the dash light you are seeing. Its a pretty complicated setup...in fact so complicated and stupid that Dodge did away with it on later models and installed new improved mechanical pendulum systems in later QC seats. No more SCTM box and solenoids are required. I comtemplated getting late model seats to do away with my SCTM...but the air bag module needs that signal to keep the warning light from coming on. And if I leave the SCTM plugged in with new seats...and I dont have the solenoids there, it senses that and will cause the dash light to come on. I was trouble shooting a system that would not let the solenoids shut off after 30 minutes of key off time. Never could solve that one.

Sorry for the long post but there really isn't any switches you can check. Except for maybe the retractor switch which senses if the belt was pulled out. But that wont make your light stay on constantly. Just a few seconds maybe. Even then you have to take your seat covers off to get to it and thats not fun.

Your best off to take it to Dodge and let them do it...or get a 99 service manual and perform all the tests. I'm not a Dodge mechanic and I'm not one to take it to them. But after all the time and money I spent on mine...I should have. After all its you safety were talking about here. And they wont let you drive away with a truck that doesn't have a functional seat belt system. They could be really liable if they did. They would have to find the problem. Its complicated to check

bent valves

The belts lock when no power is supplied to the mechanism. The reason for this is because in the event of a crash where wires are cut and power is lost, the belts will be locked. Safety verses convenience.

SIXSLUG

Thanks guys, that helps out a lot. My belts still don't lock with the truck off>30 min, windows down method, though. Wouldn't there be a code for this?

Kurt