Originally Posted by Danjo
I’m having problems with battery drain. I did a little poking around and found LED 5 on fuse block 2 lit up with the bus completely off and closed up. When I open the passenger door, the LED gets brighter. I always thought that LEDs are binary, either on or off, but that’s what I’m seeing. The legend on the fuse cabinet says that LED means the door is open. I found the switch in the manual door opener lever case and unplugged it, but the light is still glowing half-bright.
Barring any problem with door switches or sensors, my guess would be something is amiss in the BCM (Body Control Module) or LCM (Lighting Control Module). Most vehicle electrical systems today are controlled by electronic brain boxes that supply and interrupt grounds for electrical circuits based on input from switches such as what you describe.
Some of these switches are normally-closed contacts, meaning the contacts would be closed (completing the circuit) when the door is closed.
i.e., the door being closed completes the ground to the BCM, and the BCM sees the ground as a signal to command the LCM to interrupt the ground to the interior lights.
Others might be normally-open contacts, meaning the contacts would be open (interrupting the circuit) when the door is closed. In this case, the BCM would see the interruption as a signal to command the LCM to kill the lights by interrupting that circuit's ground.
In this case, unplugging the switch would do nothing -- it would simply perpetually tell the BCM to trigger the interior lights through the LCM. You might test all the door switches / sensors to ensure they are okay, then go from there. BCM / LCM issues usually require seeing a dealer.
When it does this, check to see what has power that should not (power windows, stereo, gauges powering up when they shouldn't). That will be a clue as to where the problem is. You could have a relay for Retained Accessory Power getting stuck, which could be an easy fix.
Just my $0.02.
If either of you are near Avoca, NY, you might check out South Main Auto Repair. Eric O is a crackerjack when it comes to electrical issues, but it certainly sounds like a BCM / LCM fault to me.