Troubleshooting Trailer Wiring Where Blinkers are Wired Backwards

Question:

My trailer doesn’t have a purple wire, but it does have a red wire and I don’t see anything indicating where a red wire would go. On the trailer, the marker lights on top and on the sides are working but the rear bottom are completely out. Only the left turn signal turns on and the left side brake lights come on. The trailer has 9 rear tail lights. 3 right 3 middle 3 left. The tail lights on the truck have some how turned opposite, with left turn signal on, right truck tail light flashes, right turn signal on, left tail light flashes. My trailer is 44ft. I can really use your help please, thank you

asked by: Sam S

Expert Reply:

To fix your blinker problem you need to just switch the left and right turn signal wires of the trailer wiring and you'll have them corrected. These two circuits are found in the 9:00 and 3:00 position of the connector.

If you have an extra wire that is red that you don't know where it goes it most likely is the aux cable which would connect to typically a purple wire of a 7-way. Sometimes this is also yellow.

expert reply by: Jameson C