GM Service Manual Online
For 1990-2009 cars only

Horn Relay Coil Circuit Low


Object Number: 864376  Size: MF

Circuit Description

The body control module (BCM) controls the operation of the horns for the security system and remote keyless entry (RKE) functions. Circuit 28 is grounded by the BCM when horn operation is desired. Normal operation of the horn is performed by the horn switch grounding the horn relay and is not controlled by the BCM.

There is a 30 second delay prior to setting DTC 2752 for grounded or open circuit conditions. It is possible to set DTC 2752 if the horn is operated by the horn switch for greater than 30 seconds.

Conditions for Setting the DTC

    • Horn operation not requested.
    • Circuit 28 grounded or open.
    • Conditions exist for 30 seconds.

Diagnostic Aids

    • Check for poor connection at the BCM. Inspect harness connectors for backed out terminals, improper terminal mating, broken connector locks, improperly formed or damaged terminals and poor terminal-to-wire connection (terminal crimped over wire insulation and not conductors).
    • Inspect the wiring harness for damage. Check for broken or chafed insulation.
    • If fault is suspected to be intermittent, wiggling harness wiring may help in locating fault.

Object Number: 874668  Size: FP