[header] How to wire trailer brakes [title] Find the cold side of the " stoplight " switch by probing the terminals until one is lit when the brake pedal is depressed. [step] Mark the cold wire. [substeps] The " stoplight " switch is located on the brake pedal and activates the brake lights. 
[title] Disconnect the negative battery cable of the tow vehicle. [step] Install a 2 0amp auto-reset circuit breaker as close as possible to the positive battery terminal.