Hi there, There are only normally 3 wires going to the back of the car. Tail light, stop light and fuel gauge tank sender. Normally no power to any of them with ignition or lights turned off. Whats to swap ? I don't think its fixed. The problem is up the front not at the back. Make sure your dash gauges are switching OFF with the ignition and not powered all the time. Do you have an add on electric fuel pump that is not switching off ? Do you have an add on trunk light that is staying on ? Regards, Kevin.