TRAILER WIRING

PaulRod84 · Feb 16, 2011

Hello all. I have trailer electical issue here. the lights on my trailer work fine as far a turning on when my headlights are not on, but as soon as I turn on the headlights and press the brake my lights to the trailer turn off then when the brake is let off the trailer lights turn back on. but the brake lights on my truck all work fine as they normally do, just not on trailer. does anyone know what i need to do to fix this i appreciate all the help. Thanks :?:

screwballl · Feb 16, 2011

Usually this means there is a short between the brown wire and another, usually green or yellow.

Also sometimes previous owners replace the bulbs with single filament bulbs instead of the dual filament bulbs which can cause this as well.

I would check the bulb(s) first, corrosion in the bulb sockets and related mounts second, and wiring/ground third. I would also check over the white wire grounds to see if there may be one or two ground points not making good connection. I always use a wire brush and create at least 3 grounding points on the trailer itself, usually one in the front 2 or 3 feet of the trailer tongue, and 2 more, 1 near each light.

KMixson · Feb 16, 2011

Bad ground connections can give you symptoms like that. Check your ground connections. Sometimes when a bulb blows out the filament inside will make contact with the second filament and cause erratic lighting problems. Check the bulbs.