Guardian 4389 Repair Manual page 101

DC CONTROL
replace Wire 15A from Terminal 1 to Terminal 3 of SW1.
3. No battery voltage in Step 4. Verify Step 2 and repair or
replace Wire 15 from SW1 to J1 connector.
4. No battery voltage in Step 5. Go to Test 43 or repair or
replace Wire 15A from SW1 to J1 connector.
5. If battery voltage is available in Step 8 but not in Step 7,
repair or replace Wire 17 from SW1 to J1 connector.
6. If battery voltage is available in Step 7 but not in Step 6,
go to Test 43.
7. If CONTINUITY is not measured in Step 9, repair or
replace Wire 0 between the J1 connector and the 8-tab
ground terminal.
8. If battery voltage is available in Steps 1-5 but not in Step
8 of Problem 2 flow chart, replace or repair the circuit
board.
9. If battery voltage is available in Steps 1-5 for Problem 1
flow chart, replace the circuit board.
4
1
5
2
6
3
Figure 3. Wires 15A
TEST 45- CHECK 15 AMP FUSE
DISCUSSION:
The 15 amp fuse is located on the generator console.
A blown fuse will prevent battery power from reaching
the circuit board, with the same result as setting the
AUTO-OFF-MANUAL switch to OFF.
PROCEDURE:
Remove the 15 amp fuse (F1) by pushing in on fuse
holder cap and turning the cap counterclockwise.
Inspect the fuse visually and with a VOM for an open
condition.
RESULTS:
1. If the fuse if good, go on to Test 46.
2. If the fuse is bad, it should be replaced. Use only an
identical 15 amp replacement fuse.
PART 4
15A
3. If fuse continues to blow, go to Problem 16.
TEST 46- CHECK BATTERY
DISCUSSION:
Battery power is used to (a) crank the engine and (b)
to power the circuit board. Low or no battery voltage
can result in failure of the engine to crank, either man-
ually or during automatic operation.
PROCEDURE:
A. Inspect Battery Cables:
1. Visually inspect battery cables and battery
posts.
2. If cable clamps or terminals are corroded, clean
away all corrosion.
3. Install battery cables, making sure all cable
clamps are tight. The red battery cable from the
starter contactor (SC) must be securely
attached to the positive (+) battery post; the
black cable from the frame ground stud must be
tightly attached to the negative (-) battery post.
B. Test Battery State of Charge:
1. Use an automotive type battery hydrometer to
test battery state of charge.
2. Follow the hydrometer manufacturer's instruc-
tions carefully. Read the specific gravity of the
electrolyte fluid in all battery cells.
3. If the hydrometer does not have a "percentage
of charge" scale, compare the reading obtained
to the following:
a. An average reading of 1.260 indicates the
battery is 100% charged.
b. An average reading of 1.230 means the
battery is 75% charged.
c. An average reading of 1.200 means the
battery is 50% charged.
d. An average reading of 1.170 indicates the
battery is 25% charged.
C. Test Battery Condition:
1. If the difference between the highest and lowest
reading cells is greater than 0.050 (50 points),
battery condition has deteriorated and the bat-
tery should be replaced.
2. However, if the highest reading cell has a spe-
cific gravity of less than 1.230, the test for condi-
tion is questionable. Recharge the battery to a
100 percent state of charge, then repeat the test
for condition.
RESULTS:
1. Remove the battery and recharge with an automotive
battery charger, if necessary.
2. If battery condition is bad, replace the battery with a
new one.
SECTION 4.4
DIAGNOSTIC TESTS
Page 99