B2533

CIRCUIT DESCRIPTION
The Body Control Module (BCM) controls the fog lamp relay. The BCM receives an input from the fog lamp switch input circuit. The BCM then energizes the fog lamp relay by grounding the fog lamp relay coil control circuit. The BCM will only ground the fog lamp relay coil control circuit if the following conditions exist:
^ The ignition switch must be in the RUN position.
^ The headlamp switch must be in the PARK or HEADLAMP ON position.
^ The headlamp dimmer switch must be in the LOW beam position.

CONDITIONS FOR RUNNING THE DTC
The BCM must be commanding the fog lamp relay to energize.

CONDITIONS FOR SETTING THE DTC

IMPORTANT: If the short to battery voltage is on the output side of the fog lamp switch, the fault will only set when the fog lamp switch is in the ON position.

^ The fault code will set when the output is active and a short to battery voltage is present.
^ The condition above must be present for more than 0.3 seconds.

ACTION TAKEN WHEN THE DTC SETS
The BCM stores DTC 82533 in memory.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC 82533 will clear if the short to battery in the fog lamp relay enable coil control circuit is no longer detected by the BCM.
^ A history DTC 82533 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ The BCM receives a clear code command from the scan tool.

DIAGNOSTIC AIDS
^ If the DTC B2533 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to battery in the fog lamp relay enable coil control circuit.
- The fog lamp relay coil is intermittently shorted to battery.
- The BCM is intermittently shorted to battery.

TEST DESCRIPTION

Steps 1-12:

The number(s) below refer to the step number(s) on the diagnostic table.
2. Determines that the fault is current when the for lamp relay parameter does not change state.
3. Verifies that there is a short to battery voltage in the fog lamp relay control circuit or related circuits. Not detecting a short to battery voltage would indicate that the fog lamp relay is internally shorted to battery voltage.
4. Test for short to battery voltage internal to the BCM.
5. Test for short to battery voltage on the fog lamps control circuit.