General Testing

Description:

The horn system consists of six functional components. These components are the HORN fuse, the horn switch, the horn relay, the two horns and the related wiring.

Use the following general guidelines to diagnose a horn system problem:
1. Verify the owner's complaint.
2. Check for an open HORN fuse.
3. Replace the horn relay with a known good relay and recheck horn operation. If the system checks good, replace the horn relay.
4. Check for aftermarket (non-OEM) equipment. If add-on accessories are discovered, disconnect the system to make certain that its installation is not the cause of the problem.
5. Check all connectors and related wiring to the suspect electrical component. Check for poor mating of connector halves, or terminals not fully seated in the connector body (backed out). Also check for dirt or corrosion on the connector terminals. The terminal must be clean and free of any foreign material which could impede proper terminal contact.
6. Check related ground eyelets for a clean and tight connection.

POOR HORN TONE
1. For poor horn tone: Tighten bolts/screws in mounting area, or correct poor connections.
2. For low-pitched "moaning" sound: Adjust horn current.
3. For weak horn tone: Check for poor connections. If connections are good, adjust horn current.
4. For weak, strained tone: Check for foreign object in horn or damaged horn bezel.
5. For harsh vibration during horn operation: Check for horn contact with body components.

HORN CURRENT ADJUSTMENT
Current draw for a horn while operating should be 4.5 to 5.5 amperes at 11.5 to 12.5 volts. High current (more than 20 amperes) indicates an overheated horn winding or short. If this condition exists, replace the horn. A current reading of approximately 18 amperes usually indicates that the horn contact points are not opening. If this condition exists, the horn current requires adjustment.

No current reading indicates a broken connection, an open circuit or open horn contact points. If wiring is good, the horn current requires adjustment.

To adjust horn current, perform the following procedure:
1. To increase current turn the adjusting screw clockwise. Turn adjusting screw in increments of 1/4 turn.
2. To decrease current turn adjusting screw counter-clockwise. Turn adjusting screw in increments of 1/4 turn.