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Home >> Ford >> 2005 >> Expedition 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 494 (Speed Control) >> Diagnosis And Testing >> Speed Control >> Pinpoint Tests >> Pinpoint Test A: The Speed Control Is Inoperative >> Normal Operation

Normal Operation

WARNING: This page is about a different car, the 2006 Lincoln Navigator and 2006 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

The powertrain control module (PCM) sends a signal through circuit 151 (LB/BK) to the speed control switches which passes through the clockspring. The return signal is sent through circuit 848 (DG/OG) and the clockspring. The stoplamp switch sends a voltage signal through circuit 810 (RD/LG) to the PCM when the brake pedal is applied, and deactivates the speed control if engaged. The speed control deactivator switch interrupts the power signal to the PCM through circuit 307 (BK/YE) when the brake pedal is applied firmly and passes the stoplamp switch trip point. This is a redundant signal to the PCM.