Pontiac tempest 1968 Service Manual page 370

E N G I N E E L E C T R I C A L
6E-21
These circuits are all cut off when the ignition
switch Is in the OFF or START positions.
When the ignition switch is turned to the start
position, the ignition primary circuit is activated
directly, by-passing the resistance, and the starting
motor circuit is activated to crank the engine.
Two ignition terminals, marked IGN 1 and IGN 2,
will be found on the back of switch. The IGN 1 ter­
minal is energized when the ignition switch is in
normal operating position. It directs current to the
ignition coil through the resistance. The IGN 2 posi­
tion is energized when the ignition switch is turned
to the starting position. It directs current to the
coil around the resistance to provide full battery
voltage to the coil when starting.
The two terminals V and R E G on Pontiac ignition
switch are connected to a special set of contacts
inside the ignition switch. Externally the V terminal
is connected directly to the battery splice and the
R E G terminal is connected to the No. 3 terminal of
voltage regulator. When the ignition switch is in the
ON position the special set of contacts is closed and
current flow can be traced from the battery, through
switch, through voltage regulator to the field termi­
nal of generator, and finally through the rotor field
coil windings to ground.
On all models, when the ignition switch is turned
to the start position, the ignition primary circuit is
activated directly by-passing the resistance, and the
starting motor circuit is activated to crank the
engine (Figs. 6E-31-32-33).
On Firebird models, one ignition terminal marked
IGN 1 will be found on the back of the switch (Fig.
6E-33). The IGN 1 terminal is energized when the
ignition switch is in the normal operating position.
It directs current to the ignition coil through the
resistance. In the START position, the temperature
indicator bulb check circuit is activated through the
ground.
CAUTION: Due to the presence of the bulb check
circuit which is connected to the ignition terminal,
never attempt to jumper the cranking motor sole­
noid with the ignition switch in the OFF position,
as this will result in burning of the ignition switch
ground spring.
The SOL terminal is energized when the ignition
switch is turned to the starting or crank position.
Electrical energy from the battery is supplied to the
starting motor directly through the solenoid switch
contacts to provide full battery voltage to crank the
engine.
REPLACE SWITCH
1. Remove positive cable from battery to protect
against short circuit.
2. Remove ignition lock cylinder.
3. Remove ignition switch ferrule by unscrewing
with special spanner J 7607.
4. Remove ignition switch lamp housing brace
screw from bottom flange of instrument panel.
5. Remove switch from back of instrument panel
and disconnect wires after unlatching special locking
terminal.
6. Replace switch by reversing above steps.
REPLACE SWITCH LOCK CYLINDER
1. Place ignition key in lock and depress lock
plunger by inserting small pin through hole in lock
cap.
2. While holding plunger in, turn key approxi­
mately 20° counterclockwise to release lock cylinder
and remove cylinder from switch.
3. To install lock cylinder, insert key in cylinder.
Then, with key and cylinder turned about 20° counter­
clockwise, insert cylinder in lock and rotate clock­
wise to lock in place.
FREE UP LOCK
Occasionally an ignition lock may stick, making
it difficult to insert key and turn lock. In such case
blow a very small quantity of powdered graphite into
lock key hole and operate lock several times until
lock operates freely.
If ignition switch will not free up with lubrication
it must be replaced. To remove a stuck lock, use a
3/8" drill bit and drill out center of cylinder as
shown in Figure 6E-34. The tumblers must be de­
stroyed before the cylinder can be removed.
SPARK PLUGS
PERIODIC SERVICE
Periodically (actual time depending on operating
conditions) plugs should be removed for cleaning,
inspection and regapping.
REMOVE
1. Remove spark plug wires.
2. Remove any foreign matter from around spark
plugs by blowing out with compressed air.