Circuit Description
The fog lamp relay is energized by the fog lamp switch when the body control module (BCM) has activated the enable circuit that supplies the fog lamp switch. The BCM activates the fog lamp 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 HEAD 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 enable circuit low.
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 B2533 in memory.
Conditions for Clearing the DTC
| • | A current DTC B2533 will clear if the short to battery in the fog lamp enable circuit is no longer detected by the BCM. |
| • | A history DTC B2533 will clear after 100 consecutive ignition cycles if the condition for the condition 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 Conditions and Poor Connections in Wiring Systems. |
| • | The following conditions may cause an intermittent condition to occur: |
| - | An intermittent short to battery in the fog lamp enable circuit. |
| - | The fog lamp relay coil is intermittently shorted to battery. |
| - | The BCM is intermittently shorted to battery. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Determines that the fault is current when the for lamp relay parameter does not change state.
-
Verifies that there is a short to battery voltage in the fog lamp relay control circuit or in the fog lamp enable circuit. Not detecting a short to battery voltage would indicate that the fog lamp relay is internally shorted to battery voltage.
-
Test for short to battery voltage internal to the BCM.
-
Test for short to battery voltage on the fog lamps control circuit.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Fog Lights Schematics | |||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |
Does the fog lamp relay parameter change state? | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 9 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 | |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 6 | |
6 | Test the fog lamps enable circuit of the fog lamp switch for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
7 | Test the control circuit of the fog lamp relay for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
8 | Replace the fuse block - underhood. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 12 | -- |
9 | Replace the fog lamp relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 12 | -- |
10 | Replace the IP multifunction switch assembly. Refer to Instrument Panel Multifunction Switch Assembly Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | Go to Step 12 | -- |
11 |
Important: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC set again? | Go to Step 2 | System OK |
