CAUTION: If Orange-Yellow lead is shorted to either White-Pink or Grey-Black leads it may be necessary to replace the amplifier.

Disconnect ball chain from throttle linkage. Separate servo-to-amplifier connector. Connect an ohmmeter between Orange-Yellow and Grey-Black wires at servo connector. Resistance should be approximately 85 ohms.
Connect ohmmeter between Orange-Yellow and White-Pink wire leads. Resistance should be approximately 85 ohms. Reconnect ball chain.
Start engine. Jumper Orange-Yellow lead of servo connector to battery positive post and White-Pink lead of servo connector to ground. Momentarily touch Grey-Black lead of servo connector to ground. Servo throttle actuator should tighten bead chain to open throttle. Throttle should hold in that position, or slowly release chain tension. If White-Pink wire is removed from ground, servo should immediately release tension on chain.

Fig 1: Engine Compartment Speed Control Components for Ford and Mercury Models (All Fairmont, Zephyr, Mustang and Capri, Except 302" Engine Models, are Similar)
Courtesy of FORD MOTOR CO.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Servo Assembly