Does Secondary Ground Wire on Tekonsha 3040-P Need to Be Grounded to Vehicle

Question:

Purchased the Toyota brake harness with the P3 controller. The unit powers up without the ground wire on the harness being grounded, is grounding necessary? Is the unit power draw from the main harness not enough and therefore the grounding wire is necessary? Thank you in advance for your response.

asked by: Jung L

Helpful Expert Reply:

Tekonsha determined that the brake controllers work more reliably in Toyota Trucks if the secondary ground wire is grounded to a factory grounding point or the chassis under the vehicle dash, so for the most reliable performance, I'd recommend grounding that secondary wire.

expert reply by: Mike L