To detect a break in the rear window defroster wire, turn on the ignition and the rear window defroster switch.
Connect one probe of the voltmeter to the vehicle ground, wrap the other probe with foil and move the foil along the heater conductor (see fig. 14.81).
Connect the voltmeter probe to the center of each rear window defroster wire. If the voltmeter shows about 5 volts, the defroster wire is OK. If the voltmeter shows 0 volts or 12 volts, there is an open in the defroster wire (see fig. 14.82).
To locate a break in the heater wire, connect one probe of the voltmeter to the positive terminal of the heater and move the other probe along the heater wire from the negative terminal of the heater. The point at which the voltage indicated by the voltmeter drops from a few volts to zero is the break in the heater wire (see fig. 14.83).
