Body Control System Description and Operation: Horn
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The 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 B2752 - Horn Relay Coil Circuit Low for grounded circuit conditions. It is possible to set DTC B2752 if the horn is operated by the horn switch for greater than 30 seconds.