Grand Cherokee 2WD V8-5.7L VIN 2 (2005)
Heated Glass Element: Testing and Inspection
NOTE:
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Illumination of the defogger switch indicator lamp does not necessary mean that electrical current is reaching the rear glass heating grid lines.
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For circuit descriptions and diagrams of the rear window defogger system, refer to WIRING DIAGRAM INFORMATION.
Operation of the electric backlight (EBL) system can be confirmed by the following:
1. If equipped with the automatic temperature control (ATC) heating-A/C system, use a scan tool and check for diagnostic trouble codes (DTCs)
related to the A/C-heater control. If equipped with the manual temperature control (MTC) heating-A/C system, use the A/C-heater control to check
for diagnostic trouble codes (DTCs) related to the A/C-heater control. If no DTCs are found, go to Step 2. If any DTCs are found, repair as
required, then proceed to Step 2
2. Turn the ignition switch to the On position. Set the rear window defogger switch in the On position. The rear window defogger operation can be
checked by feeling the rear window or outside rear view mirror glass surfaces. A distinct difference in temperature between the grid lines (4 and 5)
and the adjacent clear glass or the mirror glass should be detected within three to four minutes of operation.
3. If a temperature difference is not detected, use a 12-volt DC voltmeter and contact the rear glass heating grid terminal A (1) with the negative lead,
and terminal B (2) with the positive lead. The voltmeter should read battery voltage. If the voltmeter does not read battery voltage, check the
following:
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Confirm that the ignition switch is in the On position.
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Make sure that the rear glass heating grid feed wire (3) and ground wire (6) are connected to the terminals. Confirm that the ground wire has
continuity to ground.
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Check the EBL relay and the fuses located in the junction block (JB) inside of the vehicle. The relay and fuses must be tight in their
receptacles and all electrical connections must be secure.
When the above steps have been completed and the rear glass heating grid is still inoperative, one or more of the following is faulty:
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Rear window defogger switch in the A/C-heater control.
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Rear window defogger grid lines (all grid lines would have to be broken, or the power feed or the ground wire disconnected, for the entire
heating grid to be inoperative).
4. If the EBL system operation has been verified but the rear window defogger LED indicator does not illuminate, replace the A/C-heater control.
