Are you experiencing trouble with trouble code P0504? Today, we’ll be discussing the common issue of brake lights failing to respond properly, as indicated by this trouble code. Although we’ll be working on a Mazda in this video, similar problems have been reported in vehicles from other manufacturers, such as Hiundia.
In the demonstration, as I step on the brake, the lights fail to respond consistently. While pressing the brake pedal, the lights intermittently come on or fail to illuminate at all. This erratic behavior corresponds with the P0504 trouble code, indicating a problem within the circuit.
The likely solution in this case is a faulty brake switch. Typically, the brake switch is located near the brake pedal, as seen in this manual vehicle. For a visual reference, follow the brake pedal upward to locate the switch, which can be identified by its wiring. On some vehicles, the brake switch may only have two wires, while others, like the one being demonstrated, feature multiple wires.
For a two-wire brake switch, a simple continuity test can be performed by jumping the wires to determine if the brake lights respond. However, in the case of a multi-wire switch, further testing may be necessary to identify the specific wire requiring attention.
If you find yourself facing a P0504 trouble code, the likely culprit is a malfunctioning brake light switch. By replacing the switch, you can rectify the issue and restore proper brake light functionality to your vehicle.
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