To locate inoperative grid lines, turn the ignition key to the ON position and
turn the rear window defogger switch to the ON position. Attach the black lead of
the multimeter, set to the 20 volt scale, to ground. Lightly touch the red
lead of each grid line.
| • | Negative Lead for SL/SC |
| • | Zero Voltage - SW (Battery Voltage SL/SC) |
| • | Zero Voltage - SL/SC (Battery Voltage SW) |
The multimeter should display battery voltage at the positive side of each grid
line. The voltmeter should gradually display less voltage as the red lead of the
multimeter is moved toward the ground side of the vehicle.
If the reading shows battery voltage as the red lead is moved across the grid
lines and then makes a sudden jump down to zero volts, ground, that grid line has
an open in it.
Items Required:
| • | GM or Saturn Rear Window Defogger Repair Kit PN/12345345, or equivalent |
| • | Heat Gun--capable of 260°C (500°F) |
