Chart 7 Rear Defog Inoperative

CIRCUIT DESCRIPTION
The ACP provides a ground for the defogger relay when it receives a command from the IPC via the data line. The IPC times the operation initially for 10 minutes, then commands the programmer to deactivate the relay ground. Additional requests for rear defogger are for 5 minute intervals, thereafter until a new ignition cycle occurs.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.
1. This step checks to see if the rear defog relay is receiving power.
2. This step checks rear defog relay for proper operation.
3. This step decides between an open in the power source or an open in the ground.