B2753

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
CKT 28 is an input to the body control module (BCM). The BCM monitors CKT 28 in order to determine if the horn circuit is shorted. CKT 28 also acts as an output to sound the horn for RFA functions

CONDITIONS FOR RUNNING THE DTC
The BCM is commanding the horn relay ON (keyfob panic button pressed) or the horn switch is pressed.

CONDITIONS FOR SETTING THE DTC
Circuit 28 is shorted to battery positive voltage for 5 seconds

ACTION TAKEN WHEN THE DTC SETS
^ The BCM disables the horn relay control output for the remainder of the current ignition cycle. The SERVICE VEHICLE SOON indicator illuminates.

Conditions for Clearing the DTC
^ A current DTC B2753 clears when the malfunction is no longer present and the ignition switch is cycled.
^ A history DTC clears after 100 ignition cycles (from off to on) with no current codes active during the 100 ignition cycles.

DIAGNOSTIC AIDS
^ If circuit 28 is shorted to battery and the horn switch is pressed, a direct short to battery will result.
^ If the DTC is a history DTC, the problem may be intermittent. Perform the above tests while wiggling the wiring and connectors. This will often cause the malfunction to appear.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. Listen for an audible click when the horn relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the coil side of the horn relay.
4. Verifies that the body control module and horn switch are providing ground to the horn relay.
5. Tests if ground is constantly being applied to the horn relay.