Orange wire under the dash

[blueyacht]

Ok, 1976 gm straight 6 GM Mercruiser...I replaced all my guages in my boat about 3yrs ago and everything has been running fine. Recently Ive felt like my charging system was slacking and noticed that my volt guage always reads 18v while running (12.5 idle or in the off position). Looked on the back of the gauge and there was an orange (either 10 or 8 guage) atatched to it. After contacting Teleflex, they advised that only a positive and negative lead should be atatched. I disconnected it, and the volts read accurately, but WHAT IS THE ORANGE WIRE SUPPOSED TO BE ATTATCHED TO. The wire is coming directly out of the harness and is definately orange and not a faded red wire. I tried to to follow it back to the engine department, but it leads into another harness (before reaching the battery or starter) that is finely covered and I hate to unwrap it unless I have to...any suggestions?

 

[Don S]

Re: Orange wire under the dash

Did the original meter say AMP or VOLT on it. Sounds like it may have been an amp meter and what does it say on your NEW meter Volt or AMP. They are completely different. An amp meter usually has a large orange or red wire to it, but not a volt meter. An amp meter also does NOT have a ground wire on the other side of that large orange terminal.

 

[blueyacht]

Re: Orange wire under the dash

you raise a very interesting question. The new one shows as volt, but the old one is long gone. What would be the bennefit of monitoring the amps instead of the volts? If this IS for the amperage, where is it suppost to be connected to at the stern?

 

[Don S]

Re: Orange wire under the dash

The problem with amp meters is all the charging power had to go from the alternator through the amp meter and back to the battery. Usually with a lot of loss.
Since you do have a large orange wire, my guess is you used to have an amp meter, and you have now dead ended your alternator and probably fried the diodes since the volt meter doesn't feed back to the battery.
To rid your self of the dreaded amp meter, rewire your main B+ terminal from the alternator directly to the main battery terminal on the starter solenoid. Disconnect the original orange wire from the alternator and tape it off at both ends. That wire will not be used for anything any longer.
From your ignition switch, just hook up a purple wire from the ignition terminal to the + terminal on your volt meter. Hook a black wire from the - terminal of your volt meter to the ground buss under the dash.
You are now Volt meter, not amp meter.
Take your alternator to your local starter, alternator, electric motor shop and have it checked out and repaired.

 

[blueyacht]

Re: Orange wire under the dash

Firstly, thank you very much. This sounds like a plan. Only problem though is that I have a single wire alt (built in regulator) so there is no orange wire going to the alt. HOWEVER, there is one that atatches to the starter solenoid and then disappears into the harness forementioned. Time to unwravel?

 

[Don S]

Re: Orange wire under the dash

Since wires can fade and be different colors over time, here is a link to the Merc service manual Click Here to download it.
Have a look at the wiring diagram section to determine exactly what you have, will probably be a lot better than me just guessing at what you have.

 

[blueyacht]

Re: Orange wire under the dash

Thanks again, Ill let you know how things turned out

 

[blueyacht]

Re: Orange wire under the dash

from the alternator straight to the starter...14.45 (give or take)...thanks for all the help