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 headlamps 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.

TEST CONDITIONS

The CCM checks for a DTC 41 when the ignition is turned "ON."

FAILURE CONDITIONS

DTC 41 will set if the input voltage at terminal "B3" is 4.2 volts or greater.

ACTION TAKEN

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

TEST DESCRIPTION

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

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 headlight switch.

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

DIAGNOSTIC AIDS

Check connections at the CCM and the headlight switch connectors. Do the "wiggle test" on the connectors if the DTC is intermittent or a history code. This fault must be present for 2 seconds or more for DTC 41 to set.