Porsche Brake Light Switch - Valeo 9910220

Product Information

The brake light switch is a simple on/off switch that is typically located on a bracket behind the brake pedal and is responsible for activating the brake lights when the pedal is pressed. When the driver depresses the brake pedal, the switch completes an electrical circuit that sends power to the brake lights or a relay that controls them. In many vehicles, the brake light switch also plays a role in other systems, such as disengaging the cruise control or allowing the automatic transmission to shift out of park.

The brake light switch may have a few different basic styles, such as completing the electrical circuit when depressed, or when released. When they go bad, it could result in the brake lights staying on, working intermittently or blinking, or not illuminating at all. An easy way to check is to find the brake light switch on the back of the brake pedal assembly and manually activate the switch by hand. The lights should turn on and off. If they don’t, then most likely the switch is what is causing the brake light fault.

The bracket that the switch is mounted on usually has some form of adjustment. In some cases, simply adjusting the bracket may be enough to restore functional brake light operation. However, if the switch itself is bad, replacing it is an easy DIY job that will only take a few minutes. If the switch is integrated into other systems, such as the ABS, engine start/stop (that activates the engine when lifting off the brake pedal), cruise control, or transmission neutral safety interlock, then it may cause other malfunctions when it goes bad.

• Brake lights don’t illuminate: If the brake lights don’t illuminate when operating the brakes, the main culprit is a bad brake light switch
• Brake lights stay on: Depending on the style, it's possible for the brake light switch to stick or fail in the on position, constantly illuminating the brake lights
• Brake lights flicker or work intermittently: If the electrical contacts inside the switch are corroded or loose, the brake lights might flicker or work intermittently
• Cruise control won't disengage: If the cruise control is on, but does not cancel when tapping the brakes, then replace the switch to avoid creating a dangerous condition
• Car won't shift out of park: Most automatic transmissions require the brake to be pressed when shifting to drive. If the switch is bad, the transmission might not give the go-ahead to release the interlock solenoid.
• ABS or traction control warning lights: Some older ABS and traction control systems use the signal from the brake light switch to monitor if the brake is actuated, although more modern systems use a separate pressure switch on the ABS unit.
• Engine start stop won't engage when lifting off the brake: If the engine doesn't restart immediately after lifting off the brake, the switch might be bad or need an adjustment in the bracket.

About Valeo

Valeo is one of the world's largest Tier 1 OEM (original equipment manufacturer) suppliers to the automotive market because of the high quality and wide depth of expertise, spanning powertrain systems, thermal systems, comfort systems and visibility systems. In fact, Valeo is the number one supplier of OEM wiper blades and wiper systems in the world. The same high quality OEM parts are available for aftermarket replacement, so you know you will get superb quality, fit and finish in easy-to-install components.