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

asked by on September 01, 2016

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?

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.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Hello I have a 1978 Chevy four-wheel-drive. I completely tore it down and restored it and put everything back together, but the dash lights are not working properly.

Hi there. It seems that the dashboard lights are grounded to the turn signal switch circuit. This will make your dash light come on when they are not to come on. For the indicator light staying on issue is the...

What is the firing order for a 1981 Chevrolet Corvette. If you have a diagram handy that would help me out a lot. Thanks!

The firing order for the Chevy 350 is 1-8-4-3-6-5-7-2 as the distributor spins clockwise. As you know, cylinders 2,4,6,8 run along the left side of the motor (assuming you are standing in front of the car facing the engine) and...

Car starts, dashboard lights flicker, air conditioning shuts off

Hello there, thank you for asking about your 1993 Isuzu Pickup. It sounds like a bad ground in the instrument panel circuit. Looking at the wiring diagram, I see the AC heater control panel and instrument cluster share the same...

Related articles

How to Replace a Neutral Safety Switch
The neutral safety switch fails when the car will not start in neutral. The safety switch is not working if the car starts in gear.
How Long Do Brake Rotors Last?
Brake rotors, sometimes called discs, are an important component of the braking system on any vehicle. The brake rotors are the part of...
How Does the Hazard Switch Work?
When When you experience difficulties while driving like a flat tire, running out of gas, or an unfortunate accident, your vehicle can be immobile at the side of the road or worse, in an active lane of traffic. If this...