Mercedes-Benz SL550 Cruise control is not working Inspection at your home or office.

How it's done:

The mechanic will first want to connect to the vehicle’s ECU through a code reader/scanner. This will allow the mechanic to read and trouble codes and better diagnose what component may have failed.

If the mechanic determines that there is a bad fuse, he or she will find the corresponding fuse for the cruise control system to see if it has failed. If the fuse has blown, the mechanic will remove it and replace it with a fuse rated for the correct amperage.

If the mechanic believes that the brake pedal switch has failed, he or she will examine the switch to check for any superficial damage. The mechanic should then check the wiring connected to the switch and change it if necessary. When the switch has been replaced, the mechanic should make sure that both the brake lights and the cruise control system are working properly.

To check the speed sensor, the mechanic will have to get underneath the vehicle. While underneath, the mechanic will find the sensor and examine it and the surrounding wires for damage. The mechanic will then replace the sensor and then check the wires going from the sensor up to the speedometer and cruise control switches to endure that they are not frayed.

If the mechanic believes that the vacuum actuator or the corresponding hoses and cable have failed, he or she will open the hood and locate the actuator. The mechanic will first check the hoses and cable to make sure that they are in good working order. He or she will then replace the actuator as necessary.

In all of these repair scenarios the mechanic will ask to test drive the vehicle to make sure that the cruise control is working properly. He or she should also use their code reader/scanner to clear any trouble codes that may have been produced when the cruise control system was not working.