RAM 1500 Van V8-5.9L VIN Z LDC (2001)
Rear Window Defogger: Testing and Inspection
Window Defogger Grid Lines Test
To detect breaks in the grid lines, the following procedure is required:
1. Turn the ignition switch to the ON position. Set the defogger switch in the ON position. The indicator lamp should light. If OK, go to Step 2. If not
OK, see Rear Window Defogger System Control in the Diagnosis and Testing.
2. Using a 12-volt DC voltmeter, contact the vertical bus bar on the right side of the vehicle with the negative lead. With the positive lead, contact
the vertical bus bar on the left side of the vehicle. The voltmeter should read battery voltage. If OK, go to Step 3. If not OK, repair the open circuit
to the rear window defogger system control as required.
3. With the negative lead of the voltmeter, contact a good body ground point. The voltage reading should not change. If OK, go to Step 4. If not OK,
repair the circuit to ground as required.
4. Connect the negative lead of the voltmeter to the right side bus bar and touch each grid line at midpoint C with the positive lead. A reading of
approximately six volts indicates a line is good. A reading of zero volts indicates a break in the grid line between midpoint C and the left side bus
bar. A reading of ten to fourteen volts indicates a break between midpoint C and the right side bus bar. Move the positive lead on the grid line
towards the break and the voltage reading will change as soon as the break is crossed.
