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Alternator Wiring

M

mylspen

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Hi folks I'm new here and was trying find a wiring diagram and/or post about wiring in an alternator. This is a 1985 Mercruiser with a 5.7/260hp. I am taking off the original one and installing an aftermarket. It has the 3 wires or 4 if you include the ground. I have the 2 that go to the regulator, both white and one of thoses has a blue stripe. I need to know which wires go where. The alternator has a solid blue or purple and the other a solid red. I've tried seaching however I not getting what I need. Thank Mylspen
 
Ok, I see in your diagram the the main harness of the boat is purple and red. On my boat the main wires are both white with one having a blue stripe. I did notice that the pig tails on the alternator were purple and red. I think this is what I need to focus on. Thanks Myles
 
mylspen said:
Ok, I see in your diagram the the main harness of the boat is purple and red. On my boat the main wires are both white with one having a blue stripe. I did notice that the pig tails on the alternator were purple and red. I think this is what I need to focus on. Thanks Myles
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If your boat is powered my a mercruiser then either someone changed the wires or some other reason they are not the correct colors.

Follow them back to where the connect/originate and see what they connect to and that should solve your issue.

Maybe sometime along the way the original wires fried or were ruined and someone put the WRONG colored wires in place.

Red with purple stripe is 12 volts all the time, the purple is ignition on 12 volts. so what ever white wire traces back to battery voltage with key OFF then connect to red with purple stripe. the other white wire should be 12 volts with the key in the on position.
 
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This is was my plan ^^^ as I bought this boat new and nobody has played with it. Finding what wire has 12 volts when is what I needed to know. As I said earlier the main wires in the harness are white and white with a blue/purple stripe. The leads coming out of the alternator are purple and red each.

It is a marine grade unit, though the important issue is the I think is amp output. Thanks for you help.
 
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