Both Turn Signals Blink & Running Lights Not Working w/Curt Wiring Harness on 2007 Toyota FJ Cruiser

Question:

Toyota FJ Cruiser 2007. Installed wiring harness per enclosed instructions. Plugged the connectors together . Made the ground connector with the self tapping screw. Tested the outlet four wire connector and have a cross feed of left turn signal to the right turn light. The same when right turn is ed, both right and left turn flash. Also have no tail lights. Tried connecting to a trailer with the same issue.

asked by: Virgil R

Helpful Expert Reply:

Let's first make sure everything is in the right spot and none of the pins are damaged on both your 2007 Toyota FJ Cruiser and Curt wiring harness # C55567. Unplug the harness and check both its connectors and the vehicle connectors. Look for any broken or bent pins because these can cause a short. If all the pins look good then make sure the connectors with the yellow, red, and brown wires are plugged in behind the driver's side tail light and the green on the passenger's side. If any of the connectors were accidently switched this could cause issues.

If everything is correct on the vehicle side then try moving the ground to a different location. You may need to sand away on the surface down to bare metal. Also the wiring harness works best when it is grounded by itself and not with other devices.

If all of that checks out and the problem remains then there is likely a problem inside the converter box and the whole harness will need to be replaced. I recommend Tekonsha harness # 118405 because we hear about less issues with them.

expert reply by: Michael H