Pontiac FIREBIRD 1972 Service Manual page 1302

1972 PONTIAC SERVICE MANUAL
Fig. 12-35 Typical Horn Assemblies
NOTE: Only one horn is standard equipment
on some A, F and X Series.
The horn relay-buzzer is constructed to incorporate both
the horn relay and reminder buzzer into one assembly. A
typical assembly is shown in Fig. 12-36.
The horn relay-buzzer operates when the driver's door is
opened to remind him that the ignition key has been left
in the switch. A typical circuit is shown in Fig. 12-37. The
operation is explained as follows:
With the key fully inserted into the ignition switch,
the No. 4 terminal on the horn relay-buzzer is con-
CONTACTS
Fig. 12-36 Typical Horn Relay Buzzer
nected to ground through the door switch when the
driver's door is opened. Current then flows from the
battery through the coil winding, the buzzer contacts,
the ignition switch, and the door switch to ground.
The winding magnetism causes the buzzer contacts
to open, which opens the winding circuit, and the
contacts then re-close. This cycle then repeats many
times per second to give the buzzing sound. Closing
the door, or removing the key, will stop the buzzer
action.
When the horn switch is closed, the coil winding is con-
nected to ground, and the armature moves toward the
core to close the horn relay contacts. The horns are then
connected to the battery, and operate accordingly. With
the horn switch closed, the buzzer contacts remain sepa-
rated.
BACK-UP LAMPS
Back-up lamps are standard equipment on all models. On
automatic transmission equipped cars the back-up lamp
switch is incorporated in the neutral safety switch located
on the steering column. On synchro-mesh transmission
equipped cars, the back-up lamp switch is separately
mounted on the steering column. Moving the shift lever
to reverse position closes the switch and completes the
electrical circuit anytime the ignition is in the "ON" or
"ACC" position.
CIGAR LIGHTER
The lighters release automatically (usual time for release
is 10 to 14 seconds) which means that if plug is held in by
DO0 R
ENERGIZER SWITCH
Fig. 12-37 Typical Horn Relay Buzzer Circuit