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• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Headlamp Switch 12V Reference | 1 | 1 | 1 | -- |
Headlamp Switch Signal | 1 | 1 | 2 | -- |
1. Rear Fog Lamps Inoperative 2. Rear Fog Lamps Always ON |
The rear fog lamp switch signal circuit is grounded through a resistor momentarily by pressing the rear fog lamp switch. The body control module (BCM) energises the rear fog lamp supply voltage circuit which illuminates the rear fog lamp. With the rear fog lamp switch activated the BCM sends a message via serial data to the instrument cluster requesting the instrument cluster to illuminate the rear fog indicator.
Exterior Lighting Systems Description and Operation
Control Module References for scan tool information
⇒ | If the parameter does not cycle between the specified values, refer to Rear Fog Lamp Switch Malfunction. |
⇒ | If the rear fog lamps do not cycle between the commanded states, refer to Rear Fog Lamp Malfunction. |
⇒ | If the rear fog indicator do not cycle between the commanded states, refer to Rear Fog Indicator Malfunction. |
⇒ | If greater than the specified value, test the circuits listed below for a short to voltage. If the circuit tests normal, replace the S30 Headlamp Switch. |
• | Signal circuit terminal 9 X1 |
• | 12 V reference voltage circuit terminal 4 X3 |
⇒ | If less than infinite resistance, test the circuits listed below for a short to ground. If the circuit tests normal, replace the S30 Headlamp Switch. |
• | Signal circuit terminal 9 X1 |
• | 12 V reference voltage circuit terminal 4 X3 |
⇒ | If less than 7.4 kΩ, test the signal circuit and the 12 V reference circuit for a short circuit. If the circuit tests normal, replace the S30 Headlamp Switch. |
⇒ | If greater than 7.9 kΩ, test the signal circuit and the 12 V reference circuit for an open/high resistance. If the circuit tests normal, replace the S30 Headlamp Switch. |
⇒ | If not the specified range, replace the S30 Headlamp Switch. |
⇒ | If greater than the specified value, test the appropriate ground circuit for an open/high resistance. |
⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 Body Control Module. |
Ignition ON, command the instrument cluster All Indicators test ON and OFF with the scan tool. The rear fog indicator lamp should be ON/OFF when changing between the commanded states.
⇒ | If the rear fog indicator stays always on or always off, replace the P16 Instrument Cluster. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM or instrument panel cluster replacement, setup and programming |
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