Master Minder Installation

Operating Modes

The master minder can be installed to operate in one of two modes, AUTOMATIC or REMOTE engine run detection. The AUTOMATIC mode only requires 3 external connections or 4 connections if a warning indicator is desired. In this mode, the engine running condition is automatically detected by monitoring the alternator’s charging voltage on the systems buss. On installations not incorporating an alternator or if a more reliable method of detecting the engine running condition is desirable, a REMOTE engine run detection mode is available by connecting to an external engine running switch from an Oil Pressure, Hobbs, or Alternator Out indicator. Any external device providing a minimum +6.5V signal while the engine is running is suitable.

Connections

Connections are made to The Master Minder using the supplied 5-pin Molex 39-01-4051 connector and Molex 39-00-0163 female 18-24 AWG crimp pins. Wire is not supplied. The wiring harness should be fabricated to the necessary length for the installation while meeting the appropriate standards and specifications. Refer to the Molex 39-01-4051 data sheet for connector pin locations. The following table indicates the connector pins and there associated functions:

 

Pin Name Description
1 Master Switch Input from Master Switch - grounded when “ON”
2 Engine Run Input for Automatic Mode or Engine Run switch
3 Warn Light Output to Panel Indicator – grounded when illuminated
4 Keep Alive +12V Input from Battery +12V
5 Master Relay Coil Output to Master Relay coil – grounded when “ON”

 

Installation Procedure

For the following procedure, refer to the Wiring Diagram which illustrates the typical Master Switch wiring configuration and Master Minder installation wired for REMOTE and AUTOMATIC engine run detection.

  1. Disconnect the system Battery.

  2. Locate and mount the Master Minder at a convenient location near the existing master switch. The led warning indicator on the Master Minder mimics the Panel warning light and does not need to be visible when a Panel Light is installed.

  3. At the Master switch disconnect the existing Master Switch wire connecting to the low side of the master relay. Connect this master relay wire to pin 5 of the Master Minder connector.

  4. Connect a 20AWG wire from Master Minder Pin 1 (Master Switch) to the Master Switch connection, which was previously disconnected in step 3.

  5. Connect a 20AWG wire from Master Minder Pin 4 (Keep Alive) to the +12V battery buss side of the master relay. Use caution to prevent shorts as this connection will be powered by the battery at all times even when the master if off. A 5A fuse is provided internal to the Master Minder so addition fuse protection may not necessary. If AUTOMATIC engine run detection is desired, an addition connection to Pin 4 will be necessary. See step 6.

  6. If AUTOMATIC engine run detection is desired splice a short length of 24AWG wire from Master Minder pin 4 (Keep Alive) to Master Minder pin 2 (Engine Run). Go to step 8.

  7. If REMOTE engine run detection is desired, connect a 20AWG wire from Master Miner pin 2 (Engine Run) to an external engine run switch such as an Oil Pressure, Hobbs, or Alternator Out indicator that produces a minimum +6.5V signal while the engine is running and is open or less than +2.5V when the engine is not running.

  8. Connect the Master Minder pin 3 (Warn Light) to an appropriate panel warning indicator with 20AWG wire. The light should be clearly marked as a warning of a potential Master Minder automatic master shut-off condition. The light will illuminate when the master minder auto shut-off is armed and will flash for one minute before an automatic master shut-off occurs. The Warn Light output is a 1A maximum “open collector” output, grounding the powered panel light when the light is “ON”. This will accommodate most panel lights including panel lights with dimming capability.

  9. Install a second master bypass switch to override the Master Minder and prevent any undesirable Master Minder shut-off conditions. This switch should have the same specifications as the original and wired between the Master Relay and the Master Switch / Master Minder Pin 1 connection of step 3. The same master override function can be archived without an additional switch by replacing the original master with a 3 position switch wired as illustrated in the bypass wiring diagram. The Military Spec MS27408-4L 3 position toggle switch, incorporating a mechanical lock-out of the override position, is recommend for this application.