What wire circuit feeds the speed control system through the stop lamp switch?

Circuit 511 LG (light green) runs from the fuse panel through the stop lamp switch, which is closed when the brake is depressed, and on to the turn/hazard lamp circuit and speed control system.

What does the clutch switch do in this cruise control circuit?

On manual transmission vehicles, a clutch switch is placed in the 511 LG circuit; it is open when the clutch is depressed, interrupting the circuit.

What wire colors connect the speed control servo to the amplifier?

The diagram shows circuits including 140 GY/BK, 144 O/Y, 146 W/PK, 143 RD/LG, 147 P/LB, and 150 Y/R running between the servo and the speed control amplifier.

How does the vacuum dump valve work?

The vacuum dump valve vents the servo vacuum to atmosphere when the brake pedal is depressed, releasing the throttle.

What is the ground circuit for the speed sensor and amplifier?

Circuit 57 BK (black) provides the ground path, shown running from the speed sensor and amplifier to a ground point through connector C212.

Home/ Registry/ Ford/ Bronco/ 1980-1986/ 1986 Ford Bronco/ Photo supermotors.net/registry/media/826565

1986 Ford Bronco Speed Control (Cruise) Wiring Diagram - Servo & Amplifier

Manual wiring diagram of a speed control system with color-coded wires

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Wiring diagram of a vehicle speed-control system showing color-coded wires, connectors, servo and sensor components.

AI caption September 2010 · Photo 218 of 242

This is a photographed page from a Ford wiring diagram manual (EVTM-style) showing the speed control (cruise control) system schematic, filed by the uploader for a 1986 Ford Bronco. The diagram traces power from a hot-at-all-times fuse through the hazard flasher and stop lamp switch (closed with brake depressed) on circuit 511 LG, with branches for manual transmissions through a clutch switch (open with clutch depressed). The main components shown are the speed control servo — containing a regulating valve that controls vacuum applied to the servo motor and an actuator connecting to the throttle linkage — a vacuum dump valve that vents to atmosphere when the brake is depressed, the speedometer cable and speed sensor, and the solid-state speed control amplifier. Wire circuits between the servo and amplifier include 140 GY/BK, 144 O/Y, 146 W/PK, 143 RD/LG, 147 P/LB, and 150 Y/R, with ground on circuit 57 BK. Connector pinout illustrations for the speed control amplifier and servo are shown at the right and bottom of the page. A column of system-operation text on the right edge (describing SET/ACCEL and COAST functions) is largely cut off and illegible in this scan.

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Frequently asked questions

What wire circuit feeds the speed control system through the stop lamp switch?: Circuit 511 LG (light green) runs from the fuse panel through the stop lamp switch, which is closed when the brake is depressed, and on to the turn/hazard lamp circuit and speed control system.
What does the clutch switch do in this cruise control circuit?: On manual transmission vehicles, a clutch switch is placed in the 511 LG circuit; it is open when the clutch is depressed, interrupting the circuit.
What wire colors connect the speed control servo to the amplifier?: The diagram shows circuits including 140 GY/BK, 144 O/Y, 146 W/PK, 143 RD/LG, 147 P/LB, and 150 Y/R running between the servo and the speed control amplifier.
How does the vacuum dump valve work?: The vacuum dump valve vents the servo vacuum to atmosphere when the brake pedal is depressed, releasing the throttle.
What is the ground circuit for the speed sensor and amplifier?: Circuit 57 BK (black) provides the ground path, shown running from the speed sensor and amplifier to a ground point through connector C212.