Well, no. There is a ~300mA draw.
Checked underhood fuses. Nothing. Checked fuses in driver's side dash fuse box. There is a fuse in a special plastic holder labeled I.O.D. When I pull that fuse, the draw goes away. But the plastic holder prevents the fuse from coming out all the way. It's like it was designed for the fuse to be pulled out but not fall out. Weird right? And when I plug the fuse back in I hear the CD player make noises so I was thinking....oh, it's the radio.
But first, what is IOD and what's on the circuit?
Well this is hilarious. IOD stands for Ignition Off Draw. This is something I think Chrysler started doing in the 90s. Basically they put stuff that had a small current draw on this fuse and it is designed to be removed while the vehicle is in transit/storage. Insert your jokes here.
Ok, so disconnecting the IOD fuse stops the draw....now what? Clearly the draw is more than it's supposed to be. Of the many things on the circuit, what could the issue be?
Research led me pretty straight away to this seatbelt control module/timer thing. Evidently this was through 99 but not beyond. Probably because it was stupid. I don't know if this is a rollover sensor or crash sensor or what. But I can tell you when it is disconnected, the seat belts lock. Also, when I was playing around with the module I could hear the seat belt lock solenoids firing and intermittently locking. If it's a rollover sensor type thing then maybe this is normal. Sounds like something is rolling around inside. I think it is also supposed to have some 30 minute timer and I guess what happens is the drain is caused when it doesn't "shut off" after 30 minutes, which mine appears to be doing. I did disconnect and the battery draw goes to near zero.
Diagnosis of my module aside, this is apparently a common cause of both drains and locked seat belts. I did not have a seat belt issue but DO have a drain. So I need to replace it.
Of course OEM, this thing is long discontinued. So my only hope is used, or perhaps someone actually repairs these somehow.
Here's a used one for $125 plus shipping: https://www.ebay.com/itm/334399223383?e ... SwvRpiUw~X
Kinda pricey considering it's just a used part and this is a common issue.
And yes I could literally just pull that IOD fuse out, as it was intended, when I plan to let the truck sit a week. But this resets some things and I guess I just don't like this solution.