Re: Trailer Wiring
When ever you have a problem like this the first thing you want to do is determine if the problem is with the vehicle or the trailer.
To check the vehicle, first use a multimeter (ohm meter) and check the white (ground) wire of your plug to make sure you have a good ground. you should have no more than a few ohms of resistance from your plug to ground. Poor or no ground can cause all sorts of goofy symptoms. If your ground is OK, you need to test the rest of your plug with a test light. The wire (with the alligator clip) on the test light MUST be connected to a good ground, like the white wire on your plug that you just determined is good. That's why we do it first.
The brown wire on your plug is for the tail/running lights. It should have 12 volts on it only when you turn on your vehicles lights.
The green wire on your plug is for the right turn/brake light. It should have 12volts on it when you step on the brake or 12 volts going on and off when you have your right turn signal on.
The yellow should be like the green except it is for the left turn/brake light.
If all of this is in working order your problem is with the trailer.
The trailer wiring, of course, uses the same color scheme. Test without plugging the trailer into the vehicle.
White = ground. It Must be grounded to the trailer. DO NOT rely on your hitch to ground your trailer to the vehicle.
Use the multimeter once again to make sure you have a good ground. Just as you did on the vehicle. For the rest of the testing you need to run a wire from the brown lead of the vehicle plug with enough length to reach the trailer plug. Turn on your tail lights so that this wire has 12 volts on it. You don't need to turn on your headlights. Just the tail/parking lights will do.
Touch this hot wire, you just built, to the brown wire of your plug and look at your trailer lights. Both left and right tail and running/side lights should be lit.
Remove the hot wire from the brown wire, of your trailer plug and touch the hot wire to the green wire of your trailer plug. The right side trailer brake/turn signal light should light and no others.
Do the same with the yellow wire on your trailer plug to test the left side.
If one or more of these steps fails youhave found your problem or problems.
If it turns out your trailer has the problems wiring kits can be had at any auto parts store and are inexpensive.
