How to Repair Your Cruise Control System

Repairing the cruise control system in a vehicle is an extremely challenging task that should generally be done by a professional mechanic. The specifics of repairing a cruise control system largely depends on your particular model. You should refer to the service manual for your car for additional instructions. You will also need some special tools including a vacuum texture and a volt meter to be able to carry out the repairs. You will also need to diagnose and establish exactly what the problem is before spending any money on replacement parts.

Tools and Materials Needed:

  • Replacement parts, depending on the parts which are damaged
  • Safety gear
  • Mirror
  • Flashlight
  • Wiring and clips
  • Wire splicing and connecting tool
  • Pliers
  • Vacuum pump
  • Vacuum meter
  • Volt meter
  • Wrench

Step 1 – Check Fuses

The cruise control feature of your vehicle will have a fuse for it. The fuse box in your car will probably be in the passenger side glove box. It may be elsewhere, in which case you should refer to the owner’s manual for further information. If the fuse needs replacing, this is fortunately an extremely quick and easy job. All you need to do is get another fuse of the same amperage and replace the old one. To check if the old one is broken, look at it carefully under a bright light and see if the wire in the middle has snapped.

Step 2 – Carry Out Visual Inspection

To make this job easier, you should have a mirror and a flashlight. Thoroughly examine the whole installation looking for any burned out wires, snapped wires or twisted wires. If you find any damage to the wiring, you will need to replace it, using a wiring diagram specific to your car to guide you. The service manual for your vehicle will also give you further instructions on where to find the important parts. You can find all the wire connectors and wiring at any well stocked automobile store. To locate wires running to specific terminals in the system, you should use the voltmeter.

Step 3 – Use Vacuum Meter

Many cruise control systems are vacuum operated. To diagnose problems in such systems, you should start the engine and check for a vacuum in the line to the servo of the cruise control system. When the car is idle and the engine is on, the vacuum meter should reach 10 inches of mercury. If it does not, therein lies the problem.

Step 4 – Check the Throttle Linkage

If you find that the cruise control system is failing to maintain a constant speed as it should, you will also want to check the throttle linkage. Consult your vehicle's owner’s manual for further information specific to your car. This will give you further information on adjusting the linkage. If the linkage is already adjusted as it should be, you will need to check for vacuum leaks. Use a vacuum pump to apply a vacuum to the system, and you should be able to find out where the vacuum is leaking from.