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1990 Mercury 175 - outer switch box has unidentified wire

O

OldFish78

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Looking for Faztbullet - 1990 Merc 175 - cant figure where this wire comes from or goes - looked up numerous wiring diagrams none show a wire running from this pin in the outer box - green and white in no other wire attached - at a loss motor was running when investigation started - changed switch boxes on recommendation due to engine on a few occasions acting like it had a passing gear. This particular engine has rectifier appears connected correctly and voltage regulator - 16 amp stator - also idle stabilizer module still connected. Cant get picture to post but have one of the outer switch box and the wire
 
Spot on - you da man! Makes perfect sense just wonder why it's not annotated on any diagrams. However, have found the group of Mercs
1990-91 some with 16 some with 40 amp systems dont have wiring diagrams or ones I could find. Glad I got the answer because if I had
just removed it would have been trouble. I have seen the rotational sensor - could you be so kind as to explain its function?
 
Next question is wiring diagrams show green wire connection from oil lube module to outer switch box lowest pin which has green wire going to #1 coil - so any idea why mine now has a wire (cant identify color) going to pin for #4 coil??
 
Okay - not sure what or who did the wiring diagrams in my service manual but they aren't compatible. Thanks Faztbullet for setting me on the right track. Went to the boat opened the motor and traced the whole thing down - beginning to think working with these old Mercs is like philosophy - chasing a black cat in a dark room. Anyway pulled the oil lube module and it has six wires. The green wire that according to the diagram should be going to the switch box is connected with a bullet connector to a wire that might or might not be blue but it goes to the oil reservoir cap. The yellowish white and green and white wires go to the rotation sensor. Light tan/blue stripe and purple go to the terminal block correctly. The yellowish white wire goes to the outer switch box pin with the green and white stripe connection to the #4 coil - so the #4 coil is also connected thru the switch box and oil lube module to the rotation sensor - so now I now its all correctly connected - thanks to you Faztbullet and not the dang wiring diagram!! Problem solved - and in doing the research and utilizing this forum and iboats I think I can help a buddy with a 94 Merc 200 with an oil alert beep which he has paid out $2K to fix and is still beeping. As my wife tells me "if you look you will find." Thanks for your quick response and your spot on diagnosis.
 
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