If you have the fish finder, the GPS and your marine VHF radio sitting in your garage, ready to install on your boat, you can wire them yourself. The marine electronics industry and National Marine Electronic Manufacturers Association have seen to it that marine electronic systems have common, standardized wiring characteristics. If you can wire the GPS, you can wire those electronics into your boat just as well as the mechanics at your boat dealer can, and for a lot less money. All it takes is a bit of patience and some time.
Find the common power bus under your boat's dash. Your boat owner's manual should tell you where it is and probably has a drawing to show you, as well. It may be a strip with screws in it, or a series of clamps where you insert wires. The common power bus is is where you will make the power connections for your instruments.
Find your boat's common ground. Again, your boat owner's manual will provide the location. It may be a bus bar, like the power bus, with a strip with screws or clamps. It may be a grounding wire running from the bow (the front of the boat) to the stern (the back of the boat), hidden somewhere behind a panel or a series of panels. Either way, this is where you will connect the negative wires for your instruments.
Connect the external sensor (the antenna) to the electronic device ( the GPS receiver) by pushing the connector into the external input jack on the device, then turning the locking collar to the right as far as it will go. The external sensor is already grounded and will help prevent static damage to the device during installation.
Connect the power wire to the GPS by pushing the plug on the end of the power wire into the power jack on the GPS. All boat electronics have an inline fuse on the power wire, so the power wire should be readily identifiable. Check to make sure that an undamaged fuse is present in the fuse holder.
Drill holes in the control console -- if necessary -- for the mounting bracket that came with the GPS receiver. Drill the holes so that the wires can reach the power bus and common ground. Attach the mounting bracket to the console according to the directions that come with the device. Set the device next to the bracket and run the power and ground lines through the holes you made to accommodate their access to the common power bus and the common ground.
Connect the ground wire from the device to your boat's common ground by unscrewing the screw on the grounding bus with a screwdriver just enough to wrap the ground wire around the screw, then tightening the screw by turning it clockwise. Connect the power wire (the one with the fuse holder) to the power bus in the same way. Secure the device in its mounting bracket with the mounting screws provided. That's all there is to it.
- This project involves hot work with a soldering gun, working with static-sensitive electronics and a vinyl chemical coating. Appropriate cautions, including the wearing of safety glass to prevent eye injuries from close work with wiring, should be taken.
- If you need to add wire to your ground wire so that it can reach the common ground, use a soldering gun and silver solder to make a soldered connection to an extension wire of the same size as the grounding wire. Once the connection has cooled, cover it with liquid vinyl electrical coating and allow the coating coating to set.