[Main page] [How it works] [Road test and preliminary checks] [Parts testing] [Wire diagrams]

Ford Cruise Control - Preliminary checks, Road test and Common problems

WARNING! FOLLOW STANDARD SAFETY PRACTICES WHEN WORKING ON A VEHICLE INCLUDING BUT NOT LIMITED TO: Transmission in Park or Neutral and the driven wheels off the ground or chocked when cranking/running the engine.
Check fan blade for cracks and do not stand next to the fan when running.
Use caution when working on fuel systems, which can remain pressurized for a long period after the key is turned off.
No smoking around fuel.
Watch for electric fan which can come on at any time.
Watch out for hot and/or moving parts.
Watch out for high voltage secondary circuits.
If you are not sure of the safety of any operation DO NOT DO IT. ASK SOMEONE!
The author assumes no responsibility for the safety of anyone using these documents.

Preliminary checks

Do the brake lights work? Fix them if they don't. Burned out bulbs will keep the system from working.

Does the horn work? If not, check the fuse (usually the same as the cigarette lighter). If the horn fuse, relay, or wiring is bad, the switches won't get the voltage to turn the system on.

Is everything hooked up under the hood? Vacuum feed to the servo? Line on for the dump valve?

Is the cable from the Servo attached to the throttle body or carburetor? Sometimes the plastic clips that hold the cable on break or get loose enough for the cable to fall off.

Road Test

Find a safe place to do this. Not in downtown traffic.

Accelerate to about 30 mph, hit the ON switch, and then the SET\ACCELL switch. The vehicle should hold the set speed.

Hold the SET\ACCELL switch. The vehicle should increase its speed and hold it after you release the button.

Hold the COAST switch. The vehicle should slow down and hold the new speed after you release the button.

Tap the brake pedal to light the lights. The system should disengage. Allow it to slow down a bit.

Press the RESUME switch. The system should go back to the previous set speed.

Press the OFF button. The system should disengage.

Note: If some of the buttons don't work, you might try wiggling the wheel slightly as you press them. Sometimes the sliding contacts under the steering wheel get dirty and wiggling the wheel helps make contact.

Common Problems

Cruise does not work at all:
Check the fuses. The Amp gets power from the ignition switch through a fuse, but the switches also get power through the horn relay fuse (this is usually the cigarette lighter fuse also).

Throttle actuator cable broken or disconnected from the throttle.

Brake light bulbs burned out.

Cruise won't disengage when brake pedal is pushed:
Check the brake light fuse, switch and wiring.

Some switches work while others don't:
Most likely the switches are bad.

System surges:
I've seen both Amplifiers and Servos do this so it's a toss up as to what to try first. All you can do is substitute another part and try it. Problem is, a lot of places won't let you return electrical parts if you don't use them. Might try a junkyard for a used Amp to try.

System loses speed up long steep hills:
This may be normal. The system can only pull the throttle open so fast as a safety precaution. On vehicles with an overdrive transmission, it may help to turn the overdrive off in hilly areas.

If it loses speed on even small hills you may want to check the vacuum check valve in the Servo feed line. Some vehicles also had a vacuum reservoir tank to keep from losing vacuum going up hills. This would be connected to another fitting off the vacuum check valve. Check the tank for leaks if equipped.

[Main page] [How it works] [Road test and preliminary checks] [Parts testing] [Wire diagrams]

Copyright 1997-2005 Dali Design

Remove the brackets [] to email: jthorsse[@]gmail[.]com