Correcting Reversed Turn Signal Lights on Hopkins Plug-In Simple Vehicle Wiring Harness HM43415

Question:

I purchased the Hopkins HM43415 Wiring Harness for my 2000 Toyota 4 Runner SR5. Went in easy with no problems. However the turn signal lights on my trailer were reversed. Left turn was working the right signal on the trailer and visa versa. To fix the problem, I reversed the wires connecting to the lights themselves on the trailer signals and everything works fine with the 4 Runner. The problem I have is when I hook the trailer to my 2007 GMC Sierra or my 1996 Dodge Dakota the trailer turn signals are now again reversed. In other words the set up for the 4 Runner is opposite for my GMC or Dodge pick up trucks. If i switch wires on the trailer again, they work correctly with my pick up trucks but are reversed for the 4 Runner. Any suggestions

asked by: David A

Expert Reply:

It sounds like the wiring on your 2000 4Runner needs to be corrected so that the turn signal lights activate correctly and are consistent with the wiring on your other vehicles.

First make sure the tail light connectors are installed on the correct side of the 4Runner. The plug with the yellow wire should be connected at the left/driver side tail light and the plug with the green wire should be connected to the right/passenger side tail light. If this is how it is installed and the signal are still reversed then the harness wiring may be wrong.

Since the Hopkins 4-pole wiring harness # HM43415 has a connector that is shaped to allow connection in only one way the best fix is to correct the wire-to-pin assignments on the Hopkins 4-pole.

What you can do is reverse the pin connections for the yellow (left) and green (right) turn signal wires so that their signals appear on the correct pins. You can do this on either of the 4-pole connectors. You can also refer to the linked photo and article for help with how the wiring should be connected. This kind of harness assembly issue does not happen too often but it does happen once in a while. You can use 2 butt connectors like # DW05714 to make the spliced connections.

Also make sure your white ground wire is attached tightly to a clean bare metal surface.

Once you're done you can test the 4-pole with a tester like # PTW2992, shown in the linked video, to make sure the turn signals are on the correct pins or you can just plug in your trailer to test.