Purpose of the Extra Ground Wire on the 3040-P Brake Controller Connector for a 2007 Toyota 4Runner

Updated 07/26/2010 | Published 07/23/2010

Products Featured in This Question

Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional

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$169.94

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - Toyota and Lexus

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$21.06

Question:

I purchased and installed the 90195 and 3040P in my 2007 4Runner with pre-wired 7-way underdash harness. It appears to test out correctly at the rear with a 7-way connector tester. I have not connected the 3040Ps extra, white ground wire because it appears to be redundant to the white ground wire on my factory underdash connector. Is this second, separate white ground wire really needed perhaps for some heavier current draw? PS: Your website, particularly the FAQs and videos, is the most informative and complete of any site on any topic Ive ever seen. Congratulations and thanks for a site well done!

asked by: Jim M

Expert Reply:

I have noticed that the Toyota vehicles all require mounting the seemingly extra ground wire under the dash of the vehicle when installing the Tekonsha Brake Controller Wiring Harness for Pre-Wired Toyota and Lexus Vehicles, item # 3040-P. I always assumed that the ground wire is there as added protection for these vehicles sensitive circuitry.

Just to be sure, I spoke with my electrical contact at Tekonsha to see if he could give me a more detailed explanation for the inclusion of the extra ground wire. He explained that the extra ground wire is added because the ground wire that is ran to the factory brake controller is not sufficient enough to supply the proper ground for consistent brake operation.

I would definitely connect the extra ground wire to a suitable, paint, rust and corrosion free part of the vehicle chassis.

expert reply by: Robert G