When the ignition switch is in the RUN position, voltage is applied from the IP fuse 21 to the HVAC control assembly.
When the defogger switch is pressed, voltage is momentarily applied to the defog request input of the solid state timer. The timer closes the internal contacts from terminal 3 to terminal 4 of connector C5. The following actions then occur:
- The ON indicator of the switch lights.
- The coil of the rear defogger relay is grounded using CKT 193.
The defogger relay coil is supplied with voltage through the IGN E fuse of the underhood fuse block.
When the relay contacts close, voltage is applied from the underhood fuse block defogger relay through the HTD MIR fuse to CKT 2267.
This circuit supplies the following components:
| • | The left outside rear view mirror grid (finding ground at G202) |
| • | The right outside rear view mirror grid (finding ground at G205) |
The solid state timer within the HVAC control assembly controls the amount of time that the internal contacts are closed.
The defog cycle runs for 10 minutes when the following conditions exist:
| • | The ignition switch is turned to the ON position. |
| • | The rear defogger switch is turned to the ON position for the first time. |
Further operation results in 5 minute defog cycles. The defog cycle resets to 10 minutes when the ignition switch is turned to the OFF position and then turned to the ON position.
