RAM 2500 Van V8-318 5.2L VIN T Magnum CNG SFI (1997)
Heated Glass Control Module: Testing and Inspection
Before testing the defogger switch, relay, and timer module, perform the tests shown in Defogger System.
1. Remove the defogger switch module from the instrument panel heater-A/C control bezel as described, but do not unplug the wire harness
connector.
2. Check for continuity between the ground circuit cavity of the defogger switch wire harness connector and a known good ground. There should be
continuity. If OK, go to Step 3. If not OK, repair the circuit to ground as required.
3. Check for battery voltage at the fused B(+) circuit cavity of the defogger switch wire harness connector. If OK, go to Step 4. If not OK, repair the
open circuit to the Power Distribution Center as required.
4. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output circuit cavity of the defogger switch wire
harness connector. If OK, go to Step 5. If not OK, repair the open circuit to the fuseblock module as required.
5. With the ignition switch in the On position and the defogger switch in the Off position, check for voltage at the defroster relay output circuit cavity
of the defogger switch wire harness connector. There should be zero volts. If OK, go to Step 6. If voltage is present, replace the faulty defogger
switch.
6. With the ignition switch and the defogger switch in the On position, check for LED illumination and battery voltage at the rear defroster relay
output circuit cavity of the defogger switch wire harness connector. If OK, go to Step 7. If not OK, replace the faulty defogger switch.
7. With the ignition switch and the defogger switch in the On position, check for LED illumination and battery voltage at the rear defroster relay
output circuit cavity of the defogger switch wire harness connector for approximately ten minutes. If not OK, replace the faulty defogger switch.
