I have a 2004 Suburban Z71 from new. To clarify, you stopped your parasitic drain by unplugging the very top plug of door larch assembly? If that work, what is the purpose of that plug?

 

@808Burban you're replying to a 3 year old post and likely won't get a reply. The latch switch tells the BCM if the door is open or shut.

 

Hi, thanks for the reply, and yes, I knew this is an old thread. I also tested per that video and many others and can't seem to find my problem. I know the latch tells the BCM if door is closed or open, just asking if unplugging that top plug will basically end communications from latch to BCM. I've changed that latch about 3 times already and it seem to work for a couple months, then start acting up again. More so if we get rain or when the weather gets colder.

 

and you didn't think to test the wiring? throwing parts usually ends in disappointment

 

I had a shop check wiring at first, they said it was fine and wanted too much to change latch, so I did it myself. The first couple latches was the cheap $30 ones from Amazon that worked between a few days to a few weeks so replaced with a GM latch, which lasted a year or more.

 

Yes, that will end communication to the BCM without interfering with power door lock controls. When the door is open the BCM doesn't know it and vice versa.

 

so if the BCM can't see when the door is opened, it won't automatically turn off lights, radio, put BCM to sleep, etc. Seems like it could cause issues down the line.

 

Yeah, I'd only recommend it for the back two doors. Maybe you could get away with a passenger but no way with the driver.

 

The door latch switches, in principle, are no different than a basic on/off toggle switch.

The switches are normally open with the doors shut and close when the doors are opened.

The only difference between the front and rear door latches is the front doors have a separate switch for the key cylinders; but again, they work the same.

The lift gate also utilizes separate switches for the door and key cylinders.

The latches themselves not smart devices and don’t communicate with the BCM. However, the driver and passenger control switches are smart devices - they monitor the front door switch circuits and tell the BCM which state (open or closed) they are in. The BCM monitors the rear door and liftgate switches directly.

When a door is opened, the latch switch closes and the BCM looks for a reference voltage (I think it’s 5v but not sure at the moment) to be pulled low (approximately 0.5v or less).

If the latches are unplugged, the BCM will never know if the doors are opened or closed. If there’s a short to ground on the monitor circuit, that can fool the BCM into thinking a door is open when it’s not.