HORN SYSTEM OPERATION

1
HORN SYSTEM OPERATION

• CHAPTER 11

2
HORNS

• HORNS OPERATE ON ELECTROMAGNETIC PRINCIPLE
• INTERNAL DESIGN DETERMINES PITCH OF HORN
• SOME HORNS CAN BE ADJUSTED BY CHANGING SPRING
  TENSION
• USUALLY A HIGH AND LOW TONE

3
HORN

• HAS NORMALLY CLOSED POINTS
• FIELD COIL OPERATES DIAPHRAM
• DIAPHRAM OPENS POINTS
• COLUMN OF AIR VIBRATES

4
HORN SWITCH

• MOST SWITCHES ARE NORMALLY OPEN TYPE
• DEPEND ON SLIDER CONTACT WHEEL
• SPRING CONTACT BUTTON

5
SLIP RING CONTACT
6
HORN CIRCUITS

• TWO METHODS OF HORN CONTROL
• WITHOUT RELAY
• POWER SIDE SWITCH
• WITH RELAY
• GROUND SIDE SWITCHED
• MOST COMMON METHOD USED

• C324 FIG 11-10

7
HORN SYSTEM DIAGNOSIS
8
HORN PROBLEMS

• NO HORN OPERATION
• INTERMITTENT OPERATION
• CONTINOUS OPERATION
• POOR SOUND QUALITY

9
NO HORN OPERATION

• VERIFY CONCERN
• ROTATE WHEEL WHILE DEPRESSING HORN BUTTON
• USE DVOM TO PINPOINT PROBLEMS WITH RELAY SYSTEM
• SWITCH IS ON GROUND SIDE OF CIRCUIT

L384
10
HORN SYSTEM WITHOUT RELAY

• NO HORN OPERATION
• SWITCH IS ON INSULATED SIDE OF CIRCUIT
• MUST USE LARGER WIRES TO OPERATE
• AVAILABLE VOLTS

FIG 11-3 L385
11
POOR SOUND QUALITY

• ONE HORN NOT WORKING IN DUAL SYSTEM
• INTERNAL DAMAGE OF HORN
• LOW VOLTAGE TO HORN - SHOULD BE WITHIN 0.5 VOLTS
  OF BATTERY
• USE JUMPER WIRE TO TEST
• CHECK GROUND INTEGRITY

12
HORN ALWAYS BLOWS

• USUALLY CAUSED BY STICKING SWITCH CONTACTS OR
  RELAY
• USE OHMMETER TO TEST FOR GROUNDED CIRCUIT
• USE OHMMETER TO TEST RELAY (OR USE VOLTAGE DROP
  METHOD)

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HAVE A NICE DAY!
RUFUSS HORN REPAIR WE DO IT RIGHT!