System Inspection
Grid Electrical System1. With engine running, push defroster switch "ON".
2. Connect negative (-) terminal of a voltmeter to vehicle ground.
3. Using voltmeter positive (+) probe, test center of each grid line for about 6 volts.
4. If voltmeter reading is more than 6 volts, grid line is broken between center and grounded (GND) end.
5. If voltmeter reading is less than 6 volts, or 0 volts, grid line is broken between center and battery feed wire end.