Posted 2009-06-10 12:31 PM (#106251) Subject: Trailer light help please
Member
Posts: 13
i currently have no lights/brakes om my CM bumper pull and have a few questions. The other day i noticed that i had no trailer brake but i had lights. i took apart my trailer plug (7 way) and notice that the black wire in the ground position had broken off from the screw. i reattached and now have no lights or trailer brake. i checked the truck plug and all functions were working. Is the trailer grounded from the truck or is the ground wire from the trailer connected to something on the trailer. Where do i start to troubleshoot? Can a trailer plug go bad?
Posted 2009-06-10 1:11 PM (#106254 - in reply to #106251) Subject: RE: Trailer light help please
Veteran
Posts: 197 Location: MT
Take your plug back apart and check all the wires in it to make sure that some other wire hasn't broke off. Thats probably good place to start and when you checked your plug on the truck did you use a tester to make sure everywhere was getting electricity.
Posted 2009-06-10 1:25 PM (#106256 - in reply to #106251) Subject: RE: Trailer light help please
Member
Posts: 13
i did recheck the plug on the trailer and all the wires are connected. the truck was checked with a test adapter with the LEDs and everything worked ok.
Posted 2009-06-10 5:31 PM (#106264 - in reply to #106251) Subject: RE: Trailer light help please
Extreme Veteran
Posts: 420 Location: Florida
You may want to replace the plug and cut the wires back a few inches. Although things look good you may have a broken stand of wires inside the insulation. Before you do so you could make an aligator jumper bypass the male trailer plug and carry the current to each wire individually to see if the trailer lights up. And if done correctly you will even hear the braks clack on and off.
Posted 2009-06-10 9:33 PM (#106272 - in reply to #106270) Subject: RE: Trailer light help please
Expert
Posts: 2953 Location: North Carolina
Originally written by gator12513 on 2009-06-10 5:39 PM
fixed . . . forgot the coupler is ground, hooked up and all is well thanks
Relying on the coupler ball as ground is a poor practice. A film of grease or a rust could prevent full current getting to your trailer brakes or lights. A better practice is to use the ground wire built into the connectors. Voltage is not a good indicator of connectivity. A whisker thin wire can fool the voltmeter. Yet, it'll burn through when a couple of amps is applied.
Posted 2009-06-10 10:23 PM (#106274 - in reply to #106251) Subject: RE: Trailer light help please
Expert
Posts: 1205 Location: Arkansas
Agree wholeheartedly with hosspuller..........establish ground through the plug connection as intended........in the event of an accident there are people whose entire job description is to deny claims by whatever reason that can be utilized.
Posted 2009-06-11 8:28 AM (#106292 - in reply to #106251) Subject: RE: Trailer light help please
Member
Posts: 13
To use the ground from the plug you are really using the truck ground as the trailer ground, The ground wire for the trailer is connected to the truck ground but where does the ground run to for the trailer if the coupler is the ground for the trailer. Would i have to splice the ground wire into the ground coming through the plug??
Posted 2009-06-11 9:15 AM (#106294 - in reply to #106251) Subject: RE: Trailer light help please
Location: Where the wind comes sweepin' down the plain...
Lots of trailers will ground right at the end of the 7 way wire, or to one of the coupler bolts. Some manufacturers will use an eye and a pop rivet to ground. The pop rivet will loosen over time and you will lose ground. With a good trailer ground you will be surprised how much better everything will work on your trailer...especially the brakes.
Posted 2009-06-11 9:22 AM (#106296 - in reply to #106251) Subject: RE: Trailer light help please
Expert
Posts: 5870 Location: western PA
The ground wire on your trailer should be electrically and mechanically connected from the trailer frame to the ground wire in your plug. The truck's ground circuit should be the same. When your electrical plug is connected, your two vehicles' grounds should be commonly connected electrically.
The fact that the two vehicles physically touch and can share a grounding path, is not a dependable circuit. Your trailer lights and brake functions would not be reliable. They could fail under various weather conditions or even passage of a rough road.
You should not have to splice into your trailer ground wire. You might want to find where the wire is terminated with a ring terminal and screwed to your trailer frame. This usually is near the front of the trailer. You may find the wire is broken or corroded at this connection. If it isn't damaged there, again check the wire going into your plug. As was stated, the wiring can be broken inside the insulation. You can check the wire's integrity by using the ohm's scale on a multi meter while you move the wire. Make sure the plug is disconnected from the truck before you attempt this testing.
Posted 2009-06-11 9:56 AM (#106298 - in reply to #106251) Subject: RE: Trailer light help please
Expert
Posts: 5870 Location: western PA
Anywhere on the frame. The closer to the front, the less wiring you will have to use. Usually the wiring is run inside the frame to eliminate mechanical damage.
The end of the wire is stripped, and a #10 or 1/4" ring terminal is installed. A corresponding sized hole is drilled through the frame. The area around the hole is sanded and cleaned and dielectric grease is applied to all the surfaces. A stainless bolt with a lock nut and washers fastens everything together.
Trailer light help please
