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The ECU electronic control unit sit right behind the headlight switch, should be the silver box. The test is a rather long story.
You will need a multi meter set to volts.
Pull the 12 pin plug
Ign test. pin 9 12v with cruise control switch on. Also the Ignition switch set to on.
Earth test pin 4 direct earth to the body with no resistance.
Pin 8 Set button test. Put the positive probe in this slot and the negative probe earthed push the button on the stalk and you should get a 12v reading with the Ign to on position.
Pin 5 Resume test. Put the positive probe of the multi meter in this slot and operate the resume button you should get a 12v reading
Pin 3 Brake pedal test. Put your positive probe of the multi meter in this slot and the negative probe into pin 9. Ign on cruise control on should read 12v, no depress brake pedal the voltage should now drop to 0 volts. Also if you have a manual transmission depress the clutch and the voltage should drop to 0 volts.
Pin 7 Speed reading device. Run from the front wheel. Lift the wheel from the ground. Put the positive probe of the multi meter into slot 7 and earth the negative lead. Turn the wheel you should get a 0-4 volt reading. If higher it's fine.
Now make three jumper wires. Put the wires into the pin slots as follow 9-11; 1-4; 2-4. Switch the ignition on and the cruise control the fuel pedal should go down to the floor. Switch the cruise control of and the fuel pedal should return slowly.
if this step fail check for a faulty vacuum pump, or vacuum leak. If you press the brake pedal/and or the clutch pedal the fuel pedal should return from the floor.
This should answer your question but should you need more assistance please do not hesitate to ask.