Purchase and Install

• 1). Purchase a 12 volt hour meter. Most auto parts stores offer several models. Select one that is waterproof and sized correctly for where you plan to mount the meter. Selecting for other features such as digital readouts, back lighting or start and stop functions are a matter of personal choice, budget and expected use.
  
  
• 2). Choose a location to mount the meter. If you mount it close to the key switch, you most likely will be able to use the wires that come with the meter. If you choose a remote location, you may need to install wires to connect the meter to the boat's electrical system.
  
  
• 3). Measure the outside diameter of the part of the meter that will go through the dashboard or mounting panel. Most models are round so you can cut the hole for the meter with a hole saw.
  
  
• 4). Move or remove any wires directly behind where you will make the hole in the dashboard or panel to avoid them being tangled or cut when making the mounting hole.
  
  
• 5). Cut the mounting hole, insert the meter and fasten it to the dashboard. A large threaded ring that screws onto the meter on the back side of the dashboard or mounting panel holds most models in place.
  
  

Wiring

• 1). Use a 12 volt test light to locate the "run" wire on the back of the key switch. Attach the grounding clip on the test light to the negative terminal of the battery or other grounded metal object.
  
  
• 2). Turn the key switch to the "run" position. Touch the probe of the test light to the wire connections on the rear of the key switch. Two of them will be hot and light the test light.
  
  
• 3). Turn the key to the "engine off" position and retest those wire connections. Only one of them will now be hot. The one that turns off when the key switches off is the "run" wire.
  
  
• 4). Connect the positive wire (either red or black) on the hour meter to this wire using a two-port insulation displacement connector.
  
  
• 5). Connect the negative wire (either white or green) on the hour meter to the negative terminal of the battery or other grounded metal object.