Grid Filament Test
- Operate the engine at 2000 RPM. Check grid filaments with the battery at full charge. Turn on the defogger switch and measure voltage at center point "A" of suspected grid line. See Fig 1
. If reading is 6 volts, grid filament is good.
- If reading at center point "A" is 12 volts, an open exists between center point and ground side "B". Slowly move positive lead along grid filament toward ground side "B". A sudden change from 12 volts to zero volts indicates area of open.
- If voltage reading at center point "A" is zero, an open exists between center point and power side "C". Slowly move positive lead along grid filament toward power side "C". A sudden change from zero to 12 volts indicates area of open.
Courtesy of CHRYSLER MOTORS.