Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The CCM provides a 5 volt input on CKT 272, through the delay rheostat for 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."

TEST CONDITIONS

The CCM checks for a DTC 40 when the ignition is turned "ON."

FAILURE CONDITIONS

DTC 40 will set if the input voltage at terminal "B3" is 0.875 volts or less.

ACTION TAKEN

DTC 40 will set, if this fault exists for more than 2 seconds, a DTC 40 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 ground in CKT 270.

2. This test checks for a short to ground in CKT 272.

3. This test checks for a short to ground in the headlight switch.

DIAGNOSTIC AIDS

Check connections at the CCM and the headlight switch. If the problem is intermittent, do the "wiggle test" at the connections while the circuit is active.

This fault must be present for 2 seconds or more for DTC 40 to set.