[mohrds]

The rear stop light sensor works by separating the stop lamps into two circuits, each with two bulbs. The two center panel lights are one circuit and the two outside lights are the other.

The two circuits each go into a sensor and each current draw is measured. If it is not in balance (ie, one circuit has two bulbs, the other only has one working) the stop lamp on the dash triggers.

The manual tells you the only "fooled" instance. If one bulb from the center panel is burned out and one bulb on an outer light is burned out, the indicator will not come on.

It has a fail-safe so if all four bulbs are burned out (zero current flow) it triggers the light.

If you put higher wattage bulbs in the center panel but regular bulbs in the outer lights, it will trigger an indicator even though all four bulbs light.

If you replace your lights with LEDs, the light will trigger because the LEDs use next t no current, so the sensor thinks all four bulbs are burned out.

Doug