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Q: Brake switch confirmed good, but brake lights not working

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My van’s brake lights do not work; however, the turn signals, hazards, and lights do work. I removed the brake switch and confirmed that it is good and performing well. It has 2 n/c contacts and 1 n/o contact. Even though the 2 are opening and the 1 is closing, the brake lights till are not working. I am wondering if the brake light circuit goes through the ehcu. Do you think I should start considering that ehcu as the problem or is it something else?

A: The brake lights are turned on and off by t...

The brake lights are turned on and off by the brake light relay in the underhood relay box. This relay is controlled by the body control module and is signaled by the brake switch. Check the relay first to see if the body control module is operating the relay and then scan the body control module to see if it is getting a brake signal from the brake switch and sending out a signal to the relay. You may want to disconnect the battery and disconnect the body control module connectors and apply dielectric lube to the pins and reconnect it for a loose or corroded connection. If you want to have this checked, a certified pro from YourMechanic can come to your car’s location to inspect the brake light and let you know what needs repair.

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