Diagnostic Aids

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

If the DTC B2525 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 malfunction to occur:
- An intermittent short to battery positive voltage, a short to ground or an open in the fog lamp enable circuit.
- The fog lamp relay coil is intermittently shorted to battery.
- The BCM is intermittently shorted to battery positive voltage, shorted to ground or an open.

DTC B2525

Step	Action	Yes	No
Schematic Reference: Fog Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Turn ON the ignition, with the engine OFF. Place the headlamp switch in the HEAD position. Place the headlamp dimmer switch in the LOW beam position. With a scan tool, observe the Front Fog Lamp Relay parameter in the body control module (BCM) data list outputs. Turn the fog lamp switch ON and OFF. Does the Fog Lamp Relay parameter change state?	Go to Diagnostic Aids	Go to Step 3
3	Disconnect the FOG LP relay. Turn the fog lamp switch OFF. Using a test lamp connected to ground, probe the FOG LP relay control circuit at the underhood fuse block. Does the test lamp illuminate?	Go to Step 4	Go to Step 6
4	Disconnect the BCM connector C1. Using a test lamp connected to ground, probe the fog lamp relay control circuit at the underhood fuse block. Does the test lamp illuminate?	Go to Step 5	Go to Step 14
5	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 15	Go to Step 12
6	Turn the ignition to the ON position. Place the headlamp switch to the HEAD position. Place the headlamp dimmer switch to the LOW beam position. Turn the fog lamp switch to the ON position. Using a test lamp connected to battery positive voltage, probe the fog lamp relay control circuit. Does the test light illuminate?	Go to Step 9	Go to Step 7
7	Turn the ignition to the OFF position. Place the headlamp switch to the OFF position. Place the fog lamp switch to the OFF position. Disconnect the BCM connector C1. Install a jumper between the fog lamp control circuit and ground. Using a test lamp connected to battery positive voltage, probe the fog lamp relay control circuit at the underhood fuse block. Does the test lamp illuminate?	Go to Step 14	Go to Step 8
8	Test for a poor connection or an open in the fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 15	Go to Step 12
9	Turn the ignition to the OFF position. Place the headlamp switch to the OFF position. Place the fog lamp switch to the OFF position. Disconnect the BCM connector C1. Using a test lamp connected to battery positive voltage, probe the fog lamp relay control circuit at the underhood fuse block. Does the test lamp illuminate?	Go to Step 10	Go to Step 11
10	Test for a short to ground in the fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 15	Go to Step 12
11	Reconnect the BCM. Turn the ignition to the ON position. Place the headlamp switch to the HEAD position. Place the headlamp dimmer switch to the LOW beam position. Turn the fog lamp switch to the ON position. Using a test lamp connected to battery positive voltage, probe the fog lamp relay control circuit at the underhood fuse block. Does the test lamp illuminate?	Go to Step 13	Go to Step 14
12	Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement?	Go to Step 15	-
13	Replace the fog lamp relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?	Go to Step 15	-
14	Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the replacement?	Go to Step 15	-
15	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK