Mercury MerCruiser Service Manual page 341

Optional E-Stop
The E‑stop lanyard switch connection is used on Mercury outboards and can be used on MerCruiser MPI engines.
The black and black/yellow wires are connected together through a lanyard switch that is normally open. When the lanyard is
pulled and the switch is tripped, the circuit will close and ground the ECM to shut the engine off.
When this connection is not used, the wires should be kept separate and capped.
Warning Horn
The audio warning horn and connections are included with the Mercury harness assemblies. (Another horn is also supplied with
the engine for those using custom wiring systems.)
Accessory Relay Connection
The 14‑pin wiring system is able to provide up to 15 amps of accessory power to the helm through the purple wire (key
controlled) or the red wire (constant on) circuit. This harness is fuse protected on the engine with a 15‑amp fuse on the engine.
If the fuse is blown, the engine will not start or continue to run.
An accessory relay kit connected to this location can provide up to 40 amps of accessory power. The key switch will power‑up
the relay in the "accessory" position and "run" position.
Additional Relay Kit
An additional 40‑amp relay kit can be installed and connected to a junction box at the dash gauge connection location. This
location will power‑up with the key in the "run" position only.
The use of both relay kits will result in a maximum of 80 amps of key controlled power at the helm. This multiplies out on dual
engine and dual helm applications as long as the power wires to the helm are adequate to carry the total current demand.
CAN P (CAN 1) Connections
CAN P (CAN 1) data bus—Connection with a terminator resistor in place:
• The CAN P (CAN 1) data bus is terminated at each engine. Terminator resistors must be removed from the helm harness
or junction box and a jumper harness must be installed at the helm to connect the port and starboard CAN P (CAN 1) lines
together.
90-8M0099748 eng DECEMBER 2015
Relay with power harness
Accessory relay harness
© 2016 Mercury Marine
Instrumentation and Controls
25048
25144
Page 4D-11