For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2003 🢒 TopKick C-Series Commercial (Cutaway) C4/C5 🢒 Body and Accessories 🢒 Horns 🢒 Symptoms - Horns

Symptoms - Horns for GMC Truck TopKick C-Series Commercial (Cutaway) C4/C5 2003

Important: Review the system operation in order to familiarize yourself with the system functions. Refer to Horns System Description and Operation .

•	Inspect for aftermarket devices which could affect the operation of the horn system. Refer to Checking Aftermarket Accessories .

•	Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

•	Perform the following if a horn buzzes or has a harsh tone:

-	Inspect for debris in the joint where the horn fastens to the vehicle.

-	Test the torque of the horn mounting hardware. The horn mounting hardware should be tightened to a torque of 10 N·m (7 lb ft).

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

•	Horns Always On

•	Horns Inoperative

•	Horns - Poor Tone