Switches; Ignition Key Switch - Mercury MerCruiser MCM 454 Mag MPI Service Manual

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SERVICE MANUAL NUMBER 23

Switches

Disconnect battery cables from battery before testing ignition key switch with wires

still connected to switch.

1. Disconnect battery cables, if testing ignition key switch with wires connected to switch.

2. Before testing key switch, check all fuses and/or circuit breakers in electrical circuit

3. With key switch in OFF position, there should be no continuity between switch terminals.

4. With key switch in RUN position, continuity will exist between switch terminals B to I.

5. With key switch in START, continuity will exist between terminals B to I and B to S.

6. Terminals are to make contact at angles shown and to stay in contact condition as switch

7. If ignition key switch tests bad, disconnect wire connections and remove switch. Test

90-861326--1 MARCH 1999

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which could prevent operation of starter.

There should no continuity between terminal S and any other terminals.

is rotated toward START.

switch again, as in Steps 2-5, preceding. If switch tests good, wiring in harness is bad.

There should be no continuity between any harness wires with key switch removed.

Continuity, B to I Terminals

Continuity B to S Terminals

INSTRUMENTATION

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