How to Wire a Marine Stereo
When purchacing a marine radio, it is wise to avoid those with a removeable face plate. This type of radio corrodes easily at the contacts behind the face plate. Another good idea to add longevity to the new radio is to counter sink the radio sufficiently so that a plexiglass cover can be installed with a couple hinges to protect the radio from spray and other elements. The plexiglass should be tinted if the radio has an LED display. The reason for this is the LED display does not like direct sunlight and tends to fade to the point of being indistinguishable. Small pieces of plexiglass cost very little and can be purchased at any hardware store. The speakers should be made of a plastic or anything weatherproof.
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Things You'll Need
- Wire cutter
- Wire terminal crimping tool
- Box of assorted wire connectors
- Roll of shrink-wrap wire cover
- Heat source to shrink the wire covers
- Phillips screwdriver
- Common screwdriver
- Voltmeter
- Liquid electrical tape insulator
Instructions
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1
Connect the red wire, this being the main power wire, to a battery source at either the fuse terminal or the ignition switch. Use the voltmeter to find a wire that has continuous power with the key off. If working on a switched circuit, the accessory side of the switch should be used or a fuse slot on the fuse box that has power only when the key is on. When this route is chosen, the radio will only operate when the engine is running.
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2
Strip the insulation from the end of the wire and slide a short length of shrink wrap on the end of the wire. Install the appropriate terminal end and crimp it with the wire crimper. Move the shrink wrap down over the crimped end of the terminal and heat the shrink wrap until it is tight over the area. Cover the area with liquid insulator.
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3
Connect the yellow wire, which is the memory, to a continuous power source. This wire has very little draw but must have an uninterrupted power source to keep its memory alive. Connect this wire in the same way as in Step 2. Coat the connection point with liquid insulator.
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4
Connect the black ground wire to a good ground on the engine away from all moving parts and heat sources such as the exhaust. Use the appropriate circular terminal with shrink wrap for the connection point. Make sure the ground is clean of rust and tight. Heat the shrink wrap over the point of wire connection to the terminal. Coat the point of terminal connection with liquid insulator.
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5
Connect the speaker wires, keeping the colors coordinated for each speaker. For example, one speaker will have two wires of the same color with the addition of a black stripe indicating the ground wire. If the positive is gray, the gray wire with a black strip is the ground wire. Attach the wires to the speakers in this sequence: Positive to positive and negative to negative. Install the shrink wrap and then the female blade terminal. Crimp the terminal, pull down the shrink wrap and heat it to shrink it, then install the terminal on the speaker. Cover the terminal connection with liquid insulator.
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6
Duplicate this process for all the speakers using the wires of the same color for each speaker. Look at the diagram on the radio to see which colored wires operate which speakers. This is necessary so that the balance and fader functions work properly.
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Tips & Warnings
When wiring a marine stereo, precautions must be made to avoid corrosion at the connections from the salt water. Corrosion at these connections will cause a voltage drop, increased resistance, which will increase the temperature of the wire and reduced performance of the component. If there are any connections in or around an inboard motor, it could cause an explosion by igniting the gas fumes. Cover all connections with the liquid electrical tape insulator to prevent future corrosion.
