Posted: 6/5/2008 10:51:16 AM EDT
| I have a utility trailer I purchased from a friend at work a few years ago. The wiring was starting to show its age, so I decided to replace it. I purchased a kit from WalMart. Got it all together and I am having a problem. It is a 4 wire setup - yellow/brown, green/brown and white. The wires come from the adapter and run to the corresponding sides and then to the brake lights. I have the ground on one of the bolts connected to the chains. Here is the problem: Right and left blinker make the lights both sides of the trailer blink. The lights do not go on with brakes or headlights. I have a 05 F150 and I have tried using the side 4 way switch and adapter for the 7 way. I have also tried on my friends truck with the same results. What am I doing wrong? |
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First of all, I'd connect the trailer ground to the trailer plug, and make sure the tow vehicle ground is good. Don't trust the trailer hitch & ball to make a good ground. And rather than using a 7-pole to 4-pole adapter, just buy a 7-pole plug and connect the trailer wires to it. IIRC top (facing end of plug or receptacle) pole is white (ground), bottom right is green (right turn), bottom left is yellow (left turn), brown (tail/marker/tag lights) is between green & white (the plug should have colors marked on it.) A couple minutes with a test light and someone hitting the turn indicator, stepping on brakes, and turning lights on will tell you what's what on the truck. Also, I believe a 4-wire harness is made for older vehicles that didn't have separate blinker & stoplight circuits. They had a marker/tag light circuit, left turn & brake, right turn & brake, and a ground. You'll probably have to get or make a 6 or 7 wire harness. |
Clean the rust off the ball & spray w/ a little WD-40. It doesn't take much time for a thin film of rust to jack up your ground since you don't have a dedicated wire. |
Check your trailer wiring again. Sounds like the trailer is wired exactly opposite from what it should be. |
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The kit came pre-wired. The 4-way has 3 wires coming out - white, yellow/brown and green/brown. All I did was run the Yellow/Brown down the Left rear and connect to the light, run the Green/Brown down the Right rear and connect to the light, and then take the white ground and put it under the bolt holding on of the chains. I then plugged the 4-way into the plug on my truck. I don't know where I could have gone wrong. I did not hook up the 2 running lights, but they were not there before. This kit is similar to the one I purchased:Link |
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Bad ground. Ground it to the FRAME of truck. (Find a empty hole in frame you can attach terminal with a nut and bolt.) File off paint so there is bare metal connection. Then spray paint over the ground point so it doesn't corrode. With a bad ground, the current searches for a ground and usually grounds out somewhere else in the circuit causing all kinds of crazy behavior from the lights. When the main ground from the battery to the frame of a car corrodes out, car lights will act all crazy too. |
That pretty much guarantees a bad/intermittent ground. It's the only thing that could affect all of the lights on the trailer. Especially now that you know that the rest of the connections are in the right place. |
One of these? www.autoaccessconnect.com/ad7rvto4wayf.html |
 Universal Trailer Light Taillight Converter 118175 Converters are used when the tow vehicle has separate wires for turn signals and brake lights. The Modulite adds integrated short circuit protection that safeguards itself and the tow vehicle against harmful electrical shorts. 4 way flat with 60 inch lead. Modulite Tow Ready. * Stop and turn functions rated for up to 2.1 Amps per side * Taillight, clearance functions rated for up to 5.0 Amps totalone of these |