2000 Chevrolet C3500 pickup with intermittent battery drain. Installed amp meter in between battery negative post and negative battery cable. A test light can be substituted if needed but not really recommended. Let vehicle sit for about 45 minutes to ensure all modules had gone to sleep and a .85 amp drain remained.
Removed all interior fuses until drain went away. drain was on the courtesy light fuse. Unplugged door jamb switches and drain remained. Unplugged headlight switch and the drain remained. Unplugged dome light assemblies with reading lights, drain remained. Closed doors and consulted wiring diagram. Came back to vehicle to removed the delay interior light module but drain was gone. Ain’t life grand!!!
Well the only thing I could think of that I had done different before leaving the vehicle was to close the door. I adjusted the meter so that I could see it from the driver’s door and slowly opened the door. At about 2/3 open the drain came back. Closed it back to about 1/2 and drain went away. Drain is inside the driver’s door. Removed the door panel to start inspecting.
After removing the door panel, vapor barrier and speaker I had access to where I believed the short may be. I had fixed a similar problem a year or two earlier. There is a bracket that attaches the front window channel to the door and the harness is very close to it. Yep, there it is.
After gaining some room to work I found that the white wire that controls the ground side of the interior lights was indeed the culprit. According to the wiring diagram this wire in the door will activate the system even with all of the switches removed.
Not much damage so I wrapped the wire with tape and then retaped the harness.
For added protection I then place a piece of split loom around the harness.
I then positioned the wiring harness back in place but directed it away from the bracket.
Reinstalled all door components and reconnected all of the switches. retested for a drain just to be sure and all is well.