Test 47 - Check Wire 56 Voltage; Test 48- Test Starter Contactor Relay; (V-Twin Only); Test 49- Test Starter Contactor - Guardian 5240 Diagnostic Repair Manual

SECTION 4.4
DIAGNOSTIC TESTS

TEST 47 - CHECK WIRE 56 VOLTAGE

DISCUSSION:
During an automatic start or when starting manually,
a crank relay on the circuit board should energize.
Each time the crank relay energizes, the circuit board
should deliver 12 volts DC to a starter contactor relay
(SCR), or starter contactor (SC), and the engine
should crank. This test will verify (a) that the crank
relay on the circuit board is energizing, and (b) that
circuit board action is delivering 12 volts DC to the
starter contactor relay or starter contactor.
PROCEDURE:
1. Set a VOM to measure DC voltage.
2. Connect the positive (+) test probe of a DC voltmeter (or
VOM) to the Wire 56 connector of the starter contactor
relay (SCR, on models with v-twin engines) or the starter
contactor (SC, on models with single cylinder engines).
Connect the common (-) test probe to frame ground.
3. Observe the meter. Then, actuate the AUTO-OFF-
MANUAL switch to MANUAL position.
should indicate battery voltage. If battery voltage is
measured stop testing.
4. Set a VOM to measure resistance.
5. Remove Wire 56 from the starter contactor relay (V-twin
units) or from the starter contactor (single cylinder units).
Connect one meter test lead to that Wire 56. Remove J1
Connector from the printed circuit board. Connect the
other test lead to Wire 56 at J1-9 (V-twins) or J1-6 (single
cylinder units). CONTINUITY should be measured. If
CONTINUITY is not measured, repair or replace Wire 56.
RESULTS:
1. If battery voltage is indicated in Step 3, proceed to Test
48 for V-twin units or Test 49 for single cylinder units.

TEST 48- TEST STARTER CONTACTOR RELAY

(V-TWIN ONLY)

DISCUSSION:
The starter contactor relay (SCR) located in the con-
trol panel must be energized for cranking to occur.
Once the SCR is energized, it's normally open con-
tacts will close and battery voltage will be available to
Wire 16 and to the starter contactor (SC).
PROCEDURE:
1. Set a VOM to measure DC voltage.
2. Remove Wire 15 from the Starter Contactor Relay.
3. Connect the positive (+) meter test lead to the Wire 15
connector. Connect the negative (-) meter test lead to a
clean frame ground. Battery voltage should be measured.
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4. Reconnect Wire 15 to the SCR.
5. Remove Wire 16 from the SCR. Connect the positive (+)
meter test lead to the SCR terminal from which Wire 16
was removed. Connect the negative(-) meter test lead to
a clean frame ground.
The meter
6. Set the AUTO-OFF-MANUAL switch to MANUAL.
Observe the meter reading. Battery voltage should mea-
sured. If battery voltage is NOT measured, proceed to
Step 7.
7. Set the VOM to it's "R x 1" scale to measure ohms.
8. Connect one test lead to the Wire 0 connector.
Connect the other test lead to a clean frame ground.
CONTINUITY should be measured.
RESULTS:
1. If battery voltage is NOT measured in Step 3, repair or
replace wiring between starter contactor relay and fuse
(F1).
2. If battery voltage is NOT measured in Step 6 and
CONTINUITY is measured in Step 8, replace the starter
contactor relay.
3. If battery voltage is measured in Step 6 proceed to
Test 49.

TEST 49- TEST STARTER CONTACTOR

DISCUSSION:
The starter contactor (SC) must energize and its
heavy duty contacts must close or the engine will not
crank. This test will determine if the starter contactor
is in working order.
PROCEDURE:
Carefully inspect the starter motor cable that runs
from the battery to the starter motor. Cable connec-
tions must be clean and tight. If connections are dirty
PART 4
16
15
COM
0
Figure 3. The Starter Contactor Relay
DC CONTROL
16
NO
56 0