Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The CCM provides a 5 volt input on CKT 272, through the delay rheostat of the twilight sentinel portion of the headlight switch and returns to the CCM via CKT 270. The delay feature is only used to control the amount of time that the headlights and park lamps remain "ON" after the ignition switch is turned "OFF".

The CCM uses internal sense on CKTs 272 and 270 to check for opens, and shorts to battery voltage.

DTC WILL SET WHEN

The ignition is turned to "RUN," and the input voltage at terminal "B3" is 4.235 volts or greater for more than 2 seconds.

ACTION TAKEN

DTC 41 will set. A short to B+, or open in CKT 272 or CKT 270 will disable the twilight delay function

DTC WILL CLEAR WHEN

Will clear if the fault goes away for 2 or more seconds

DTC CHART TEST DESCRIPTION

Number(s) below refer to circled number(s) on the diagnostic charts.

1. This test checks for a short to B+ in CKT 270.

2. This test checks for an open in CKT 270.

3. This test checks for a short to B+ in CKT 272.

4. This test checks for an open in CKT 272.

5. This test checks for a short to B+ on the headlamp switch.

6. This test checks for an open on the headlamp switch.

DIAGNOSTIC AIDS

Check connections at the CCM and the headlamp switch connectors. Do the "wiggle test" on the connectors if the DTC is intermittent or a history DTC.