Parasitic drain

120,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
MICHAEL GOSNEY
  • MEMBER
  • 16 POSTS
Well, I have been testing my friends Jeep and just occasionally tinkering and found that when I unplugged the BCM, the spark when putting the terminal on the post, was not even noticeable.
I did get them to get a new battery, and I started the jeep and it runs smoothly and no warning lights in the dash come on. Just the one rear passenger door indicator still says it is open.
It would not throw any codes either since there was no power for so long. I did remove the door latch and only found that you must replace it as there is no way to repair it. But strangely, the red indicator light I think is for alarm system, is on top of the dash, not in it, it stays on solid instead of flashing. I fixed their Honda's heater core so it has not been a priority for the Jeep but it does seem as though I have found the main issue for drain yet the solid red light does seem suspect.
Nov 25, 2018 at 10:45 PM
Advertisement
Avatar
STEVE W.
  • ✓Experienced Mechanic
  • 15,385 POSTS
If the rear door latch is not telling the BCM that the door is closed, the BCM will not fully shut down and can cause a drain because it will nor shut off other modules as well. The security light issue could also be related to that as the system checks all the doors to verify they are latched prior to it arming the system.
Nov 25, 2018 at 11:55 PM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle