Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The headlamps relay coil circuit is part of the headlamp system. The CCM is able to control the headlamps via CKT 691. In addition to the CCM control of the headlamps, the headlamps can also be turned "ON" by grounding CKT 691 at the RCDLR and TD module or the headlamp switch.

DTC WILL SET WHEN

The headlamp enable circuit stays near battery voltage when the CCM is trying to take it to ground to enable the headlamps to come "ON." This fault can only set when the CCM commands the headlamps "ON," if the fault lasts longer than 2 seconds.

ACTION TAKEN

DTC 34 will set. Headlamps will not come "ON" at all.

DTC WILL CLEAR WHEN

DTC 34 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 chart.

1. This test checks for a short to B+ in CKT 691.

2. This test checks for an internal short in the relay between terminals "30" and "86", which would cause a short to battery condition.

3. This test checks for an internal short in the relay coil.

4. This test checks if problem is in headlamp switch.

5. This test checks if problem is in Remote Control Door Lock Receiver/Theft Deterrent (RCDLR/TD) module.


DIAGNOSTIC AIDS

Do not turn the Headlamp Switch "ON" while DTC 34 is current. The headlamp switch may short out due to excessive current flow in CKT 691.

If the DTC is a history DTC, the problem may be intermittent. Refer to "Intermittents/History DTCs". Intermittents/History DTCs A Tech 1 can be used to activate the headlamp relay.