Manitowoc 3900W - Page 186

TROUBLESHOOTING CHART
F = Fuel Gauge P = Pressure Gauge
T= Temperature Gauge A=Ammeter
Symptom Possible Cause Corrective Action
No gauge indication. 1. Empty fuel tank. (F) 1. Fill tank.
2. No power to gauge. (F,P,T,A) 2.
3. Broken wire between gaugeand sending
unit. (F,P,T)
4. Sending unit not grounded. (T,P,F)
5. Loose drive belt or defective pump. (P)
6. Insufficient amount of fluid in tank. (F,P)
7. Clogged fluid line. (F,P)
8. Engine not sufficiently warm. (T)
9. Defective sending unit. (F,P,T)
10. Defective gauge. (F,P,T,A)
11. Dead battery. (A)
12. Blown fuse. (F,P,T,A)
13. Loose or broken alternator belt. (A)
14. Defective regulator. (A)
15. Defective alternator (diodes burned out).
(A)
16. Defective resistor or shunt. (F,P,T,A)
.
Loose or broken wire from power source.
Replace or tighten.
Replace wire.
4. Check for rust on mounting screws.
5. Tighten or replace belt; repair or replace
pump.
6. Add fluid to tank.
7. Remove foreign material from line.
8. Let engine idle a few minutes.
9. Replace sending unit.
10. Replace gauge.
11. Recharge or replace battery.
12. Replace fuse.
13. Tighten or replace belt.
14. Replace regulator.
15. Replace or repair alternator.
16. Replace resistor or shunt.
Excessive pointer
fluctuation.
1. Loose wire connections. (F,P,T,A)
2. Loose drive belt or defective pump. (F,P)
3. Restricted fluid line. (F,P)
4. Clogged filtel ~. (F,P)
5. Defective regulator. (,~)
6. Loose alternator belt. (A)
7. Defective sending unit. (F,P,T)
8. Defective gauge.. (F,P,T,A)
1. Check and tighten all wiring.
2. Tighten or replace belt; replace or repair
pump.
3. Remove restriction.
4. Replace filter.
5. Replace regulator.
6. Tighten belt.
7. Replace sending unit.
8. Replace gauge.
Full scale indication
at all times.
1. Wire to sending unit grounded. (F,P,T)
2. Improper connections at posts on rear of
gauge. (F,P,T)
3. Gauges not properly grounded. (F,P,T)
4. Defective regulator. (A)
5. Defective sending unit. (F,P,T)
6. Defective gauge. (F,P,T,A)
1. Replace Wire and check and tighten all
wiring connections.
2. See Figure 1 for proper connections.
3. See Figure 1 for proper connections.
4. Replace regulator.
5. Replace sending unit.
6. Replace gauge.
Indicating inaccuracy.
1. Loose connections. (F,P,T,A)
2. Improper resistor. (F,P,T)
3. ImProper shunt. (A)
4. Improper sending unit. (F,P,T)
5. Defective sending unit. (F,P,T)
6. Defective gauge. (F,P,T,A)
1. Tighten all wiring connections.
2. Check part number and replace.
3. Check part number and replace.
4. Replace with proper sending unit.
5. Replace sending unit.
6. Replace gauge.
FOLIO 1194-4
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