Troubleshooting Trailer Lights Dim and Flickering When Towing W/ 2017 Toyota Highlander

Question:

The Trailer lights are dim and flicker when driving but work fine when parked. Can the ground on this harness be modified like the Curt version? Is the Curt version better at overcoming the ground at the hitch ball?

asked by: David K

Expert Reply:

I would be happy to help!

The ground on the Tekonsha T-One Vehicle Wiring Harness # 118449 you have on your 2017 Toyota Highlander cannot be modified to be grounded directly to the frame like the Curt # C56217 you mentioned. The # 118449 gets its ground through the factory connector.

Now there should be no reason that the # 118449 would cause the ground issue, but there are a few things you can check. Remove the connectors from the factory harness and look for any bent pins or debris that could be causing the ground issue.

More than likely the issue is a bad ground on the trailer tongue. This is the main ground and can cause all sorts of issues if it is bad. Check to make sure it is securely connected to clean corrosion free metal.

I included videos of the products mentioned for you to take a look at.