Pontiac FIREBIRD 1972 Service Manual page 1274

12-4 1972 PONTIAC SERVICE MANUAL
HORNS OPERATE INTERMITTENTLY
CAUSE
Loose or intermittent connections in horn
relay or horn circuit.
Defective horn switch.
Defective relay.
Defects within horn.
CORRECTION
Check and tighten connections.
Replace switch.
Replace relay.
Replace horn.
HORNS BLOW CONSTANTLY
CAUSE
Sticking horn relay.
Horn relay energized by grounded or shorted
wiring.
Horn button can be grounded by sticking
closed.
CORRECTION
Replace relay.
Check and adjust wiring.
Adjust or replace damaged parts.
NOTE: Most horns with burned open windings
are caused by one of above malfunctions.
Before replacing horns with open windings
with new horns check to make sure that none
of above conditions exist which would again
cause horn winding to bum open.
IGNITION KEY BUZZER INOPERATIVE
CHASSIS CHECK
If the key buzzer does not operate with the key fully
inserted in the lock cylinder, with the driver's door open:
Check the horn operation. This shows that the power
is available to the horn relay. If the horn does not
operate, consult the manual as to the method of re-
pair.
Check the door jamb switch by opening and closing
the driver's door and observing the dome light oper-
ation. If the light does not work, repair, replace, or
adjust the switch as required.
Check the horn relay to insure that the buzzer wire
is connected.
If the results of these three checks are normal, proceed to
the harmonica (a multiple wire connector), which con-
nects the column to the chassis. Separate it and connect
jumper wire between the "E" and "F" female contacts
(marked on connector body) on the chassis side (Fig. 12-
3).
At this point, one of two things will occur; the buzzer will
either sound or it will not. If it does not sound, the prob-
lem is in the chassis end of the harmonica connection.
Even though the horn did sound, the buzzer part of the
horn relay could be defective. By grounding the # 4 termi-
nal of the horn relay, the buzzer should function. If it does
not, replace the horn relay.
If the buzzer sounds when the " E and "F" contacts of
the harmonica are connected, the fault is in the column
part of the circuit.
COLUMN CHECK
1. Buzzer Switch and Lock Cylinder Check
-
Disassem-
ble the upper end of the column until the buzzer
switch leads are visible. With the key fully inserted in
the lock cylinder, check the continuity of the buzzer
switch. With a probe at each lead, the meter should
light. If it does not, the fault has been isolated to the
switch or lock cylinder.
2. Lock Cylinder Inspection
-
Remove the lock cylinder
and check the actuator tip when the key is fully
seated and removed (Fig. 12-4).
If this tip will not protrude from the cylinder approx-
imately 1/8" with the key fully inserted, replace the
lock cylinder. If this cylinder is physically damaged,
it should be replaced.