Testing of potential problems
Before starting any diagnosis, always check if any aftermarket items have been added to the vehicle. If the vehicle is equipped with any aftermarket items, disconnect them to verify that these items are not the cause of the issue.
Test whether the voltage is normal.
- Connect the negative lead of the voltmeter to a known good ground.
- Connect the positive lead of voltmeter to the selected test point. It may be necessary to turn on the ignition of the vehicle or set it to accessory to check the voltage.
- Read the multimeter value to determine whether the terminal voltage is normal.
Test whether the circuit is open.
- Set the multimeter to ON or resistance.
- Connect the positive pole of the multimeter to one side of the line.
- Connect the negative electrode of the multimeter to the other side of the line.
- Read the multimeter value to determine whether the circuit is open.
Test whether the line is short-circuited to ground.
- Set the multimeter to ON or resistance.
- Connect the positive pole of the multimeter to one side of the line.
- Connect the negative electrode of the multimeter to the body ground.
- Read the multimeter value to judge whether the circuit is short-circuited.
Test whether the component resistance is abnormal.
- Set the multimeter to resistance.
- Connect the positive electrode of the multimeter to one side of the component.
- Connect the negative electrode of the multimeter to the other side of the component.
- Read the multimeter value to judge whether the resistance of the component is abnormal.
Test whether the fuse is blown.