Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

CKT 149 is used to complete the electrical circuit for the courtesy lamp system. CKT 149 is grounded by the CCM when the CCM gets a request to activate the roof rail and door courtesy lamps.

TEST CONDITIONS

The CCM test for a ground/open in CKT 149 when it is not trying to activate the courtesy lamp system.

FAILURE CONDITIONS

This fault will only set if the courtesy output is "OFF" and the Delayed Interior Lighting (DIL) relay has been enabled to come "ON."

ACTION TAKEN

DTC 25 will set.

TEST DESCRIPTION

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

1. This test checks to see if courtesy light system is functioning.

2. This test checks for a defective CCM or short to ground in CKT 149.

3. This test checks I/P fuse 27.

4. This test measures CKT 149 voltage at CCM C2 connector terminal "C12".

5. This test checks for B+ at DIL relay terminal "B3".

6. This test checks to see if voltage is going out to CKT 823.

DIAGNOSTIC AIDS

If the DTC is a history code, the problem may be intermittent. Try performing the test shown while "wiggling" wiring and connectors; this can often cause the fault to appear. Check for poor connections at both the CCM and the delayed interior light relay connector; these could cause an open or an intermittent fault. Refer to "Intermittents/History Codes/Poor Connections". Intermittents/History DTCs

If CKT 149 is shorted to ground, the courtesy lamps will be "ON" until illuminated entry, or delay interior lamps time out. If CKT 149 is open, the courtesy lamps will be "OFF" at all times.

If following trouble trees for test 3 in diagnostic chart, make sure ignition is "OFF" and CCM has gone to sleep before checking for short to ground in CKTs 740/823.

A Tech 1 can be used to activate the DIL relay.