2nd Gen Non-Engine/Transmission 12V Power Situation

[Ncostello]

Upon testing some wiring in my 99 Quad Cab... I noticed something strange. The Run-Acc power supply to my Seat Belt Control Module has 12V full power at the module when the key is on... thats good.



When the key is turned off, the power should go to 0. 00 Volts. Instead it goes to about 1. 5 Volts and continues to go down over time. I think it eventually goes to 0. 00 although I get tired of waiting and have not checked this for sure.



What would cause this slow power bleed off? I would think the power should immediately be 0 when the key is turned off. This power wire goes back to the Ignition Switch through the "Seat Belt" fuse in the junction block. It then makes its way back to the Power Dist. Center under the hood. According to the wiring diagram/schematic in the manual... . there is really nothing else in the way except the fuse. Is my ignition switch most likely at fault? Can they get dirty and transmit energy across the terminals? I bet a new one isn't cheap.



PS: I thought maybe this "super" low voltage bleed was causing my SCTM to remain on all the time. But I have pulled the "seat belt" fuse which surely cuts the "Run-Acc" power to the SCTM. And my SCTM (retractor solenoids) still remains on (energized) all the time. But thats another story all together.

 

[Sticks]

This thread is about someone that was having a problem with battery drainage. It talks about the timer that the seatbelt actuator stays active after key off.



Hope this helps.



Sticks

 

[Ncostello]

Thats my thread also. Like I mentioned in my last sentence, the SCTM is another story altogether. All I'm interested in here is why my run-acc power leads remain somewhat energized and bleeds off after the key is turned off. I was just thinking maybe my ignition switch is the culprit. After all when its off... the power is supposed to be "gone".

 

[Sticks]

Oops, my bad. Coffee hasn't kicked in yet.



It's possible for the contacts behind the key tumblers to have a build up of conductive material (dirt, lint, copper dust from the contacts), and act as a bridge between contacts. I would remove the ignition switch assembly and take it apart and clean it before I replace it. I don't know how they are put together on the Dodge, but you should be able to do it with out taking apart the tumbler assembly.





Sticks

 

[Ncostello]

Thanks sticks... I'm gonna take it apart tonight.

 

[15w40]

The Airbag Control Module uses a storage capacitor to insure airbag operation in the event of a crash where the batteries become disconnected. I suspect that you are seeing this storage capacitor bleeding down.