Chart F Improper Rear Defogger Operation

CIRCUIT DESCRIPTION

The programmer provides a ground for the defogger relay when it receives a command from the ECC Head via the data line. The ECC Head 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 tests for continuous voltage across terminals 2 and 5 of the rear defogger relay. When the defogger is commanded off, normally, there should not be any voltage.

2. This tests for an inoperative condition due to absence of power to the ECC Head.

3. This tests for a faulty ECC Head commanding the rear defogger on continuously.

4. This tests for a short to voltage on CKT 192.

5. This tests for an open circuit in CKT 50.

6. This test for a faulty relay.

7. This tests for either an open in CKT 291 or a faulty Programmer.