Dodge ram truck 3500 1996 Service Manual page 494

8L - 4 LAMPS —
D I A G N O S I S A N D T E S T I N G ( C o n t i n u e d )
FOG LAMP DIAGNOSIS
B R
C O N D I T I O N
P O S S I B L E C A U S E S C O R R E C T I O N
FOG LAMPS ARE DIM
W I T H E N G I N E IDLING
OR IGNITION TURNED
OFF.
1. Loose or corroded
battery
cables.
2. Loose or worn generator
drive belt.
3. Charging system output
too low.
4. Battery has insufficient charge.
5. Battery is sulfated or shorted.
6. Poor lighting circuit Z 1 - g r o u n d .
7. Both fog lamp bulbs
defective.
1. Clean a n d secure battery cable clamps a n d posts.
2. Adjust or replace generator drive belt.
3. T e s t a n d repair charging s y s t e m , refer to G r o u p 8 A .
4. Test battery state-of-charge, refer to Group 8 A .
5. Load test battery, refer to G r o u p 8A.
6. T e s t for voltage drop across Z1-ground locations,
refer to Group 8 W .
7. Replace both lamp bulbs.
FOG LAMP
BULBS BURN OUT
FREQUENTLY.
1. Charging system output
too high.
2. Loose or corroded terminals
or splices in circuit.
1. Test a n d repair charging system, refer to Group 8A.
2. Inspect a n d repair all connectors a n d splices, refer t o
G r o u p 8W.
FOG LAMPS ARE DIM
W I T H E N G I N E
RUNNING ABOVE IDLE.
1. Charging system output
too low.
2. Poor f o g lamp circuit
ground.
3. High resistance in f o g
lamp circuit.
4. Both f o g lamp bulbs
defective.
1. Test a n d repair charging s y s t e m , refer to Group 8 A .
2. T e s t voltage d r o p across Z 1 - g r o u n d , refer to G r o u p 8 W .
3. T e s t a m p e r a g e d r a w of f o g lamp circuit.
4. Replace both fog lamp bulbs.
FOG LAMPS FLASH
RANDOMLY.
1. Poor f o g lamp
circuit g r o u n d .
2. High resistance in f o g
lamp circuit.
3. Faulty fog lamp switch
circuit breaker.
4. Loose or corroded terminals
or splices in circuit.
1. Repair circuit g r o u n d , refer to Group 8 W .
2. T e s t a m p e r a g e d r a w of f o g lamp circuit.
3. Replace f o g lamp switch.
4. Repair connector terminals or splices, refer to Group 8 W .
FOG LAMPS DO
N O T I L L U M I N A T E .
1. Blown fuse for f o g lamps.
2. No ground at fog lamps.
3. Faulty f o g lamp switch.
4. Broken connector terminal
or wire splice in f o g
lamp circuit.
1. Replace fuse, refer to group 8 W .
2. Repair circuit g r o u n d , refer to Group 8 W .
3. Replace f o g lamp s w i t c h .
4. Repair connector terminal or wire splices.
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