Mercury MERCRUISER, Service Manual, Page: 327 / 566

3. The DMT should indicate battery voltage. If battery voltage is not present, check the circuit breaker and battery power
interface for a loose or dirty connection or damaged wiring.
a - Connector location
b - Purple and red/pink connector
c - Ground terminal
4. Connect the positive (+) DMT lead to the purple lead and the negative (–) DMT lead to the ground terminal.
5. Turn the ignition switch to the "ON" position.
6. The DMT should indicate battery voltage. If battery voltage is not present, check the ignition circuit (purple lead) for a loose
or dirty connection or damaged wiring.
a - Connector location
b - Purple and red/pink connector
c - Ground terminal
Battery Will Not Recharge
Possible Cause Remedy
Excessive current draw from battery. Turn off non‑essential accessories.
Alternator drive belt loose or in poor condition. Replace or adjust.
Unacceptable battery condition.
Test battery, replace if necessary.
Loose or dirty electrical connections or
damaged wiring.
Check all associated electrical connections and wires (especially battery cables).
Clean and tighten faulty connections. Repair or replace damaged wiring.
Faulty alternator Test alternator output, replace if necessary.
A
C O M
m A
V H z
mV
V
H z TEMP
m A
A
IG
IP OFF
H z
TEMP
29371
b
c
a
A C O M m A V H z
mV
V
H z TEMP
m A
A
IG
IP
OFF
H z
TEMP
b
c
a
53695
Charging System
90-8M0099748 eng DECEMBER 2015 © 2016 Mercury Marine Page 4C-13