All lights work on the truck, only the right turn and brake lights won't work on the trailer connector (both 4 pin & 7 pin connectors)
Hey Boon,
The pinouts for a 7-way plug are as follows:
Seven wire Trailer plugs:
Horse, stock or utility trailers:
White = Ground - 1
Blue = Electric Brakes - 2
Brown = Tail and clearance lights - 3
Black = Battery, aux power - 4
Yellow = Left turn/Brake - 5
Green = Right turn Brake - 6
Orange or Purple (not both) = Auxilliary or Reverse - 7
Recreational Vehicle:
White = Ground - 1
Blue = Electric Brakes - 2
Green = Tail and clearance lights - 3
Black = Battery, aux power - 4
Red = Left turn/Brake - 5
Brown = Right turn Brake - 6
Yellow = Auxilliary or Reverse - 7
In both cases 4 is battery and 7 is reverse, aux or not used.
Double check your wiring using these lists as a reference.
Click here for my post on Trailer wiring
This should get us closer to the answer.
Best regards,
Mike
I had that problem. I purchased a engine diagnostic and trouble . code reader and cleared the DTC. it took about 3 times. I then purchased a Super Chip Tuner from Summit Racing and installed the new tuning , I then checked the trailer lights (brake and turn lights) they are working fine!! now. I think when I first cleared the DTC,s that fix it. or The Super Chips Tuner fix the problem. Martin
Sounds like a short in the wires between the vehicle wiring and the trailer plug. probably a corrosion problem because most poeple, including the factory, don't protect the trailer harness as well as they should. i would replace the wires that go to the specific contacts with the problems, if you want the cheap way. if you want the best way replace everything from the body harness all the way, including the 4 and 7 pin connectors. Napa sells a great combo connector that i use on nearly all vehicles. whatever you do, remember, there is no such thing as too much electrical tape or heat shrink. put a good protective layer of something on the harness to protect it against the elements.
Did you check for power with a test light right at the connectors?? If so, follow and visually check the wiring from the connectors back to the "t plugin", which is the point where the wiring to the trailer connectors tee off the wiring to the truck tail lights. The 7 pin has a separate connection for brake lights but the 4 pin doesn't... 4 pin connectors have Left turn/stop, Right turn/stop, Park (tail) light, and ground, so it uses a combination of left turn and right turn for the brake lights...
Did you check for power with a test light right at the connectors?? If so, follow and visually check the wiring from the connectors back to the "t plugin", which is the point where the wiring to the trailer connectors tee off the wiring to the truck tail lights. The 7 pin has a separate connection for brake lights but the 4 pin doesn't... 4 pin connectors have Left turn/stop, Right turn/stop, Park (tail) light, and ground, so it uses a combination of left turn and right turn for the brake lights...
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4 way flat molded connectors allow basic hookup for three lighting functions; right turn signal / stop light (green), left turn signal / stop light (yellow), taillight / license / side marker (brown) and a ground (white).
4 way tow vehicle side.
4 way trailer side.
5 Way Systems
Same as 4 way system listed above but adds a extra blue wire for brake signal or auxiliary power. Used on pop up camper trailers or utility / boat trailers.
5 way tow vehicle side.
5 way trailer side.
6 Way System, Rectangle Plug
3/4 inch by 1 inch 6 way rectangle connectors right turn signal (green), left turn signal (yellow), taillight (brown), ground (white). The red and blue wire can be used for brake control or auxiliary. Use on a small motorcycle trailer, snowmobile trailer or utility trailer. Can also be used as custom wiring on trailers with 3 light/wire systems. See "Tow Vehicle Taillight Wiring" below.
6 way tow vehicle side.
6 way trailer side.
6 Way Systems, Round Plug
Round 1 1/4" diameter metal connector allows 1 or 2 additional wiring and lighting functions such as back up lights, auxiliary 12v power or electric brakes. Note: The black (sometimes red) 12v and blue electric brakes wire may need to be reversed to suit the trailer. Check with a test light or VOM. Uses: horse trailer, travel trailers, landscaping trailer, car trailer, etc.
6 way tow vehicle side.
6 way trailer side.
7 Way Systems
Round 2" diameter connector allows additional pin for auxiliary 12 volt power or backup lights. Uses: heavy duty landscaping trailer, car trailer, boat trailers, horse trailer, travel trailer, construction trailer, etc. Check with a test light or VOM.
7 way RV flat blade tow vehicle side.
7 way RV flat blade trailer side.
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