Alternator; Charging System Inspection - Mercury V6 175 Diagnostic Manual

Charging and Starting System
The alternator is equipped with two fans that induce air flow through the alternator to remove heat.

Alternator

H
a
A
4 1
A
c
H
1 4
a - PCM connector A
b - Hot stud (battery +)
c - PCM connector C
d - Fusible link
e - Alternator output
f - Alternator 4‑pin connector
Connector
A B

Charging System Inspection

1. If the problem is an undercharged battery, verify the condition has not been caused by excessive accessory current draw
or by accessories that have been left on.
2. Check the physical condition and state of charge of the battery. The battery must be at least 75% (1.230 specific gravity)
charged to obtain valid results in the following tests. If not, charge the battery before testing the system.
3. Inspect the entire charging system wiring for defects. Check all connections for tightness and cleanliness, particularly the
battery cable clamps and battery terminals.
IMPORTANT: The alternator output lead (black with red sleeve) connection must be tight. A darkened red sleeve indicates
the lead was loose and became hot. Verify the output lead attaching nut is tightened to the specified torque.
a
Page 6B-6
A1
ORN
G2
H4
A1
C1 PPL
102B
H4
Pin Wire Color
A Orange
C
D
B N/A
C Purple
D Red
65696
© 2018 Mercury Marine
109B
d
109A
Not connected at the alternator; not used
12 V wake circuit (+) ‑ used as the excitation lead
12 V battery power (+) ‑ used as the alternator sense lead
a -
b -
b
66511
b
RED
e
RED
RED
D
C
PPL
B
ORN
A
Function
Not used
Alternator output lead/fusible link, to hot stud
Alternator connection to engine harness
(excitation and sense leads)
90-8M0146617 eng JULY 2018
f
65445
PCM
AG2
–
CC1
–