5 - 9
5 Electrical Troubleshooting
Ignition Switch Tests
Figure11. Testing the Ignition Switch
Figure 9. Ignition Switch Wire Harness (As Viewed
From Engaging End)
G
M
OFF
RUN
START
Figure 10. Testing the Ignition Switch
B. Test Power to Ignition Switch
NOTE: Some later model units use an ignition switch
with a sixth terminal. The sixth terminal isolates the
alternator from the rest of the electrical system dur-
ing engine shut down. The remaining five terminals
function exactly the same as five terminals switches
and will not effect the test procedures contained in
this section. When the sixth terminal is to be tested,
it is referred to as terminal “A.”
1. Pull plug off ignition switch.
2. Set VOM to VDC
3. Probe negative to ground. Probe the "B" receptacle
(see Figure 9) on the ignition switch plug. The VOM
should show battery voltage. If not, check the bat-
tery, circuit breaker, and all connections.
4. Reinstall the ignition plug.
B
L
OFF
RUN
START
C. Test Ignition Switch
1. Remove the plug from the ignition switch.
2. Remove the ignition switch from the dash board.
3. Set VOM to Ohms.
4. With key switch in the OFF position connect test
leads to terminals G and M. The VOM should show
continuity.
Six Terminal Switches: G to A and M to A should
also show continuity.
5. Check all other connection combinations for no conti-
nuity. G to M (G to A and M to A) should be the only
combinations that have continuity; all other connec-
tion combinations should have no continuity.
6. With the key switch in the RUN position, connect the
VOM to terminal B and terminal L. The VOM should
show continuity.
Six Terminal Switches: B to A and L to A should also
show continuity.
7. Check all other connection combinations for no conti-
nuity. B to L (B to A and L to A) should be the only
combinations that have continuity; all other connec-
tion combinations should have no continuity.
B
G
L
M
S
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