Mercury Tach wiring. What goes where?

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w2much

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Coming out of my control box are 5 wires, purple, black, brown / white and tan. Which ones go to the tach. Rewiring console took out birds nest of wire and am starting fresh. Also have an ampmeter and a trim tilt gauge. Will diregard the trim tilt gauge because there is no sender on the engine. Can ya help me out. Thanks. This is a 1989 100 HP 4 cyl Mariner ( Mercury)
 
Barnacle_Bill

Barnacle_Bill

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Re: Mercury Tach wiring. What goes where?

Purple is 12V from switch
Black is ground
Should be a gray wire which is tach input
Brown/white goes to "S" on trim gauge
Tan goes to alarm horn
 
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w2much

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Re: Mercury Tach wiring. What goes where?

I just looked again and you are correct. Have grey wire and one of the tan wires has a blue stripe on it. Where does the tan with blue stripe go? Thanks for your reply as I am working on this project as we speak.
 
Silvertip

Silvertip

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Re: Mercury Tach wiring. What goes where?

Are you sure you have an "amp" meter? If it is, it is wired very differently that a "volt" meter. If the dial reads -20 0 +20 or some such range its an amp meter and it will say Amps or Amperes on the face. If its a volt meter it will read 0 - 18 or so and it should say Volts on the face. If it is indeed an amp meter I would replace it with a Voltmeter which is far more valuable for electrical system monitoring.
 
Barnacle_Bill

Barnacle_Bill

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Re: Mercury Tach wiring. What goes where?

My manual doesn't show a tan with blue strip. Trace it back and see if someone has spliced it to another wire.
 
Dunaruna

Dunaruna

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Re: Mercury Tach wiring. What goes where?

[colour=blue]Tan wire & Tan/Blue stripe serve the same purpose - Temp switch to horn (warning buzzer).
 
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w2much

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Re: Mercury Tach wiring. What goes where?

Thanks for the info. Yes it was a volt meter. So I hooked it up and watched my tach dance around a bit. The tach was already wired under the dash and I left its harness as it was as the previous owner said that it worked. The control box was removed and the wires were cut about 9" from where they exit the control box. From there the wires were a raindow of colors not corresonding to the wires of the original harness . So I'm thinking that the tach is bad as it has been sitting for a number of years.Thank you all for your help.
 
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