So I was running wires for a aftermarket amp and changing out the door speakers in my 2014 R56 Cooper S. I disconnected the positive battery cable the first day to remove the front seats. Reconnected the positive terminal when I was done for the day. The car started with no issues.

I disconnected the positive terminal the very next day to complete the instal job. Reconnected the terminal and the car was completely dead. No lights, door locks, windows and radio. It was like there was no battery in the car at all.

I went the very next day and bought a brand new battery, put it in and still absolutely nothing. I had to have it towed to the Mini dealership here in Dallas and the technicians cannot figure out what is wrong with my Mini either 🥺 Not sure what to do or what’s wrong with it.

  • 1
    If the dealer who has possession of the vehicle cannot ascertain what's wrong, you should take the car to a different mechanic or dealer. Commented Jun 14, 2022 at 15:47

1 Answer 1


I would start by opening the main fuse box and probing the fuses with a voltmeter to see if there is power to any of the fuses. Start with the largest fuses you can see in the fuse box.

Connect the negative probe of the voltmeter to the battery negative then use the voltmeter positive to probe the fuses.

Report back with what you find.

You didn’t accidentally connect the battery the wrong way round at any time did you?

  • I was wondering along the lines of either your last sentence, or wondering if the battery is not getting fully connected. Commented Jun 14, 2022 at 19:40
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    @Pᴀᴜʟsᴛᴇʀ2 I was thinking that and was going to add it to my answer, but you would have thought the dealer would have at least checked the battery was connected properly.
    – HandyHowie
    Commented Jun 14, 2022 at 20:26
  • Thank you guys for the answers. Yeah the battery is connected right and the terminals are clean with a good connection. Dallas Mini Dealership is horrible and so is their communication. I think I will have to physically go up there if I want any answers. Commented Jun 16, 2022 at 19:47
  • Update- So I received the problem and the estimate for repair. The problem, the main engine wiring harness was cut through at the engine firewall. The price to replace the part with labor…$17,300!!!! $1000 for the part and over $16k for labor!!! WHAT THE ACTUAL F$&@???? I paid $17,500 for the car! So I will be towing the car back to my house and attempt to connect the cut wires myself. Pray for me guys, I’m going to need it!!! Commented Jun 18, 2022 at 0:44
  • Did they explain how this could have happened? I have never heard of anything like this happening before. Can you add a photo? Other than it may be in a difficult place to work, a repair shouldn’t be too difficult.
    – HandyHowie
    Commented Jun 18, 2022 at 7:45

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