Poor Ground Connection Causing Both Trailer Turn Signals to Blink

Question:

ON my 2021 Jetta when I turn either turn signal the lights on the trailer blink like emergency switch. I installed T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector ITEM # 118791 QTY: 1

asked by: Ron R

Expert Reply:

The symptoms you mention are typically caused by a poor ground connection, either at the trailer connector on the vehicle, the connector on the trailer or at one of the trailer lamp's grounding points.

Make sure that the ground wire of the Tekonsha # 118791 is securely attached to the vehicle frame or chassis. I like to place a star washer between the vehicle surface and the ring terminal, the washer will bite into the metal for a secure, reliable connection. The same goes for the main ground on the trailer. Follow the white wire from the trailer connector, typically the main ground is located somewhere on the trailer tongue. Make sure this connection is secure and not corroded.

Each individual trailer lamp assembly will also have its own ground connection, either via its mounting hardware that connects it to the trailer, or via a separate ground wire. If the lamps ground via the mounting hardware, make sure the lamps are mounted the trailer frame or to metal that's in direct contact with the trailer frame. If they aren't, run a jumper wire from the hardware to the trailer frame.'

I'll link to our trailer wiring troubleshooting article which you might find helpful..

expert reply by: Mike L