Heated Glass Element: Description and Operation

Voltage is applied at all times through Circuit Breaker 24 to the contacts of the Defogger Relay. When the Ignition Switch is turned to RUN. voltage is applied through Fuse 3 to the coil of the Defogger Relay. The coil is grounded through the BLU (291) wire to the Heater and A/C Programmer when the following conditions are met and the Defogger is requested. The engine must be running and the hard top must be connected (C319) or the soft top must be up.


When the Defogger Switch is pushed, the Climate Control/Driver Information Center (CCDIC) sends information to the Body Computer Module (BCM) through the Data Line. The BCM also receives inputs to determine if the Hard or Soft Top is connected. The BCM sends information to the Heater and A/C Programmer through the Data Line. The Heater and A/C Programmer energizes the Defogger Relay closing the relays contacts. With the contacts closed, voltage is applied to the Rear Defogger through the PPL (192) wire. Voltage is also applied through Fuse 20 and the PPL/WHT (293) wires to the Outside Mirrors. The Hard or Soft Top Defogger and Outside Mirror Defoggers are heated for 10 minutes the first time the Defogger Switch is pushed. During the same ignition cycle the Hard or Soft Top Defogger and Outside Mirror Defoggers can be turned on again by pushing the Defogger Switch. Each additional time the Defogger Switch is pushed, the Hard or Soft Top Defogger and Outside Mirror Defoggers are heated for 5 minutes.


Whenever the Defogger Switch is pushed, the Indicator on the CCDIC lights. At the end of the time-out the BCM sends information to the Heater and A/C Programmer through the Data Line and the Relay is de-energized. The Defogger Indicator will then turn off.