The Dual MAP selection switch is a normal on/off switch that is connected to the ECU. When it is on it will connect the input to earth, this indicates to the ECU which map is required. Note: The ECU only tests this switch at startup and not on the fly. The reason is that all the maps have to be uploaded from flash memory and then new settings must be implemented. So the ECU must be switched off and on again to change to the alternate map. The other reason is that the Map switch is used as a flat shift input during riding.

Wiring

The Mercury2 ECU does not have a dedicated input for the Dual MAP selection switch. It can be selected on one of three inputs if any of them have not been used by the tuner. The inputs are Cam 2, fuel pressure sensor input and altitude sensor input. Cam2 does not always function correctly due to the capacitor isolator. Try and keep the wire to the switch as short as possible. The dashboard on/off switch selects which map will be used. If not connected it will default to Map 1 at startup. If the switch is on, it will be Map 2.

Altitude Sensor
The 6-way connector pin 2 which is the altitude input. Open is map 1 and close is map 2. This is the preferred sensor to use.

Fuel Pressure Sensor
The 6-way connector pin 4 which is the fuel pressure input. Note that here a 1 K pull-up resistor is required to 5 volts. Do not connect it to 12 volts. It will damage the ECU. Open is map 1 and close is map 2.

Cam 2 input
The 12-way connector pin 5 which is the cam 2 sensor input. Open is map 1 and close. It may require a 2K pull-up to the ignition power of the ECU.