The ignition switch mounted on the instrument panel at the left of dash light is a combination switch and theft proof lock. This type of lock carries the highest classification of the Underwriter's Laboratories.
When the lock cylinder is "in," the ignition circuit is broken and the car locked. To unlock the switch, turn the key one fourth turn to right at which time the lock cylinder springs out and closes the ignition circuit. The key is not required to lock the car and should be removed after the operation of unlocking is completed
To lock the switch, press the cylinder completely in. BE SURE THAT IT STAYS IN.
Mechanical protection for the "switch to distributor wire" is accomplished by enclosing this wire in a steel cable. The grounding of the ignition switch takes place both through the lock casing and through the attachment at the distributor.
A diagram showing details of the electrical circuit of which the switch is a part is shown
in Fig. 442.
Should ignition trouble develop, check battery connections, also yellow wire from terminal box to starting motor and black wire from terminal box to coil, also red wire from coil to switch. If these connections and wires are O. K. check switch as follows:
Remove the four screws which hold the instrument panel in place and pull panel back. Disconnect wire at terminal"A,"(Fig.441) on the lock case.
The switch may then be tested in the following manner by using a six volt circuit and test lamp.
First test:With breaker points in distributor open,
place one test point on the primary terminal "D" inside the distributor (see Fig. 441) and the other test point on the switch terminal “A,” (Fig. 441) With the switch unlocked the test lamp should light—with the switch locked the lamp should not light.
Second test: Place one test point on the primary terminal"D,"(Fig.441) inside the distributor as in the first test and the other test point on the switch casing "B." With the switch locked, the lamp should burn. With the switch unlocked, the lamp should not burn.
If the lamp lights with the switch locked as described in the first test or if the lamp lights with the switch unlocked as outlined in the second test there is either a ground in the switch, or the distributor condenser is shorted or grounded and it will be necessary to dis connect condenser from distributor to deter mine whether the trouble is in the switch or condenser.
To remove the condenser from the distributor, remove the sealing wax covering screw head, see "C,"(Fig.433) and back out the screw. Remove screw at “A,” (Fig. 432) and remove condenser "B."
For test purposes, insert a new condenser in place of the one removed and again try the second test as outlined above. Should the lamp still burn when the switch is in the unlocked position, the trouble lies in the switch and it should be checked as follows:
Unlock the switch. Remove the three screws which hold the switch to the back of the instrument panel. The lock cylinder can then be removed by taking out the set screw "C" at the side of the lock casing (see Fig. 441). Test the two contact buttons inside the switch housing to see that they are free and have
spring pressure back of them to make good contact with the lock plunger. See that lock plunger is clean and that the insulating washers are in place.
If the above tests fail to locate the trouble, it is no doubt due to a break in the wire in the cable and it will be necessary to replace the conduit assembly with the exception of the lock cylinder. The lock cylinder and keys in the old assembly can again be used.
When necessary to remove the switch or conduit assembly from the car, remove bolt which fastens cable to engine, remove distributor from cylinder head and unscrew distributor from switch cable.
Should the lock cylinder not work freely on account of dirt or foreign matter getting into the lock case, the cylinder should be removed and cleaned until it works freely.
Never grease or oil the lock cylinder. If the tumblers stick, place a little graphite in the keyhole.