Battery BNS controller problem?? need help...
Thread Starter
Newbie
Joined: Oct 2011
Posts: 5
Likes: 0
2004 SL500 Kleeman
Battery BNS controller problem?? need help...
2004 SL500 with Kleeman supercharger, 33k miles. The car sat for some time. It started right up but the rear battery was dead. I replaced the rear battery but the red battery light is still on and the top will not lower. I took it into the shop that installed the kleeman kit and the mechanic says that he is unable to communicate with the battery controller or BNS? The 100A fuse on the passenger side is good. Is this common? How would it go bad from sitting? I drove it a few times with the bad battery before replacing it.
Is my only option to replace the BNS at $750 simply because the car sat and the battery died? Can you buy this BNS used or must it be paired to the car specifically? This is ridiculous! I've had cars and trucks sit for 2 years and fire right up without the battery even going dead!!!
Is my only option to replace the BNS at $750 simply because the car sat and the battery died? Can you buy this BNS used or must it be paired to the car specifically? This is ridiculous! I've had cars and trucks sit for 2 years and fire right up without the battery even going dead!!!
Junior Member
Joined: Feb 2012
Posts: 17
Likes: 0
C300
Sl's trunk seals leak. This is a pretty common problem on these cars. I would check to see if there is any moisture or water in the trunk under the carpeting if the car sat outside (assuming you live in an area that gets precipitation). Most common is for the water to take out the PSE pump which would affect your roof operation. It can also blow fuses so make sure you check all fuses. The pse fuse is in the compartment behind the pass seat.
Newbie
Joined: Jun 2019
Posts: 1
Likes: 1
07 MB SL55
BNS Controller
2004 SL500 with Kleeman supercharger, 33k miles. The car sat for some time. It started right up but the rear battery was dead. I replaced the rear battery but the red battery light is still on and the top will not lower. I took it into the shop that installed the kleeman kit and the mechanic says that he is unable to communicate with the battery controller or BNS? The 100A fuse on the passenger side is good. Is this common? How would it go bad from sitting? I drove it a few times with the bad battery before replacing it.
Is my only option to replace the BNS at $750 simply because the car sat and the battery died? Can you buy this BNS used or must it be paired to the car specifically? This is ridiculous! I've had cars and trucks sit for 2 years and fire right up without the battery even going dead!!!
Is my only option to replace the BNS at $750 simply because the car sat and the battery died? Can you buy this BNS used or must it be paired to the car specifically? This is ridiculous! I've had cars and trucks sit for 2 years and fire right up without the battery even going dead!!!
