Electrical issues after jumping another vehicle's battery?

KYBROWN96

MEMBER
2021 JEEP COMPASS
2.4L
4 CYL
4WD
AUTOMATIC
75,000 MILES

Our friend tried to jump their car with ours while it was in his driveway, he said he ruined our battery and when we got it back a bunch of stuff was disconnected. My husband jumped it and reconnected everything that was disconnected but now the power steering won't work, the radiator fan doesn’t kick on and it over heated sitting at Walmart while it was snowing last night and the warning lights on the side mirrors stay on the whole time it’s started. These are the warning messages that come up when starting. 1. Dynamic service torque 2. Blind spot alert 3. ACC/FCW unavailable 4. Service power steering 5. Service esc system... We checked all and any fuses it could be which were all fine and switched some out that were the wrong amperage as well.

Monday, December 16th, 2024 AT 2:29 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
50,346 POSTS

Yep, sorry about that, it sounds like the battery was jumped backwards. Can I ask when you checked the fuses for the system did the fuses have power with the key on?

This guide can help:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If not, I would check the codes for the CAN because it sounds like the BCM has shorted out. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is how to change out the BCM, you can get a preprogrammed unit by searching Google or Ebay. Check out the images (below). Please let us know what happens.

Images (Click to make bigger)