Brake sensors - how many ohms should they read? Front reads different from the back.

[Rainier]

Good Afternoon,
I'm troubleshooting my brake light on the panel, it stays on constantly. As you know the brake sensor connects to a plug about 12 inches from the sensor down on the wheel. I disconnected the sensor in the back and connected my multimeter into the plug and had a reading of 5M ohms. I then plugged the rear sensor back in and then tested the front of the car and it registers an open. Infinite ohms. I followed front wheen wiring up into the car and to the fuse panel but didn't find any broken wires.

Does anyone know what the sensors are supposed to read? And does anyone know where this wiring goes? I appreciate any and all help offered. Thanks - Rainier

[citizen_insane]

The way the sensor works to my knowledge is that it's just a loop of wire. The way the sensor detects a worn brake pad is that it gets worn through by rubbing on the rotor and goes open. I'd say if the sensor is reading open, that means it's been used and you need to replace it.

[nando]

It's basically just a wire that breaks when the pad gets worn. Infinite ohms means the sensor is dead.

[jeffnhiscars]

I don't remember the last sensor I installed in a brake pad. I just zip tie them in a tight loop and they NEVER go bad.

If you aren't looking at your brakes more often then when the pads wear out you shouldn't have an e30 :)