Circuit Description
The foglamp relay is controlled by the body control module (BCM). Positive voltage is applied to the relay coil when the headlamp switch is in the park or head position. The BCM grounds the foglamp relay control circuit in order to turn on the foglamp relay. When the foglamp relay control circuit becomes shorted to battery positive voltage, DTC B2533 is set.
Conditions for Running the DTC
| • | The ignition switch is on. |
| • | The headlamp switch is on. |
Conditions for Setting the DTC
All of the following conditions must be met:
| • | The ignition switch is on. |
| • | The headlamp switch is on. |
| • | The foglamp relay control circuit is shorted to battery positive voltage for 250 milliseconds. |
Action Taken When the DTC Sets
| • | The foglamps are always on when the headlamps or parklamps are off. |
| • | The foglamps are inoperative when the headlamps or parklamps are on. |
Conditions for Clearing the DTC
| • | A current DTC B2533 will clear when the malfunction is no longer present. |
| • | All BCM history codes clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles. |
Diagnostic Aids
| • | The fog lamps will only illuminate under the following conditions: |
| - | The parklamps or low beam headlamps are on. |
| - | The highbeam headlamps are off. |
| - | The fog lamp switch is on. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This action may cause the malfunction to appear. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Listen for an audible click when the foglamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
-
Tests for voltage at the coil side of the foglamp relay.
-
Verifies that the body control module is providing ground to the foglamp relay.
-
Tests if ground is constantly being applied to the foglamp relay.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Lighting Systems Diagnostic System Check? | Go to Step 2 | |
Does the foglamp relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 8 | Go to Step 5 | |
Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 6 | |
6 | Test the control circuit of the foglamp relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
7 | Test the control circuit of the foglamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the foglamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
10 | Repair the coil side feed circuit of the foglamp relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the foglamp relay. Did you complete the replacement? | Go to Step 13 | -- |
12 |
Important: Perform the set up procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration . Replace the body control module. Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
