P0565

Step 1: Verify the cruise control master ON/OFF switch operates mechanically and that its indicator light (if equipped) illuminates when pressed. If no indicator, proceed to electrical testing.

Step 2: With key on, backprobe the cruise control ON signal wire at the ECM connector. Toggle the ON/OFF switch and verify a clean voltage transition (typically 0V to 12V or vice versa). No change indicates a circuit fault.

Step 3: Check the cruise control fuse in the fuse box. A blown fuse removes power from the switch circuit entirely. If the fuse is blown, check for shorts before replacing.

Step 4: Test continuity of the ON signal wire from the switch connector through the clock spring (if routed through the steering column) to the ECM connector. An open circuit at any point will prevent the signal from reaching the ECM.

Step 5: If wiring is intact, disconnect the switch and measure its contact resistance in both ON and OFF positions. A good switch should show near 0 ohms when closed and infinite resistance when open. Replace if contacts are worn or intermittent.