Service wear on brake pads

[clowntrigger]

I am getting the Brake Wear service wear on brake pads warning. I pulled all four wheels and checked that the pads had plenty of life. I also checked continuity across the sensor and they all read 0 ohms, so there are no shorts. What else can I check to track this down?

2002 996 C4 Cab

[Loren]

Are you sure you read the brake wear sensor and not the speed sensor?

Brake sensors are across A1 and A2 unplugged and out of the circuit.

[clowntrigger]

I traced the wires from the actual brake pads to where they plugged into the harness.There is a single wire that runs from the harness to the brakes and it runs in series from one pad to the next at each wheel. My guess is the wire is broken somewhere in the car harness.

[clowntrigger]

Is there a wiring diagram I can get for this circuit? I've checked the pads and sensors several times and they're in good shape. The break has to exist somewhere else and I'd like to track this down and resolve it.