Gauge wiring screwy

[Starcraftnewbie]

So I’m having an intermittent crank/no crank situation. New ignition switch installed. Same problem, I noticed that the purple wire runs to each gauge but at the last gauge in the daisy chain it jumps over to the dark blue wire that provided power to my gauge lights. From what I’ve read that shouldn’t be. The blue wire should go to my navigation light switch to provide power. I’m wondering if the purple wire providing power to gauge function and gauge lights is too much of a draw. If I jump 12v from blue wire motor starts no problem every time. I don’t wanna wire it that way because my gauge lights would always be on. Any help please. Am I in the right track.

 

[achris]

Hello Starcraftnewbie and :welcome: aboard.

First up, what are you working on? (Engine year, model, and if it's a Mercruiser, serial number).

Having the blue (gauge lights) wire connected to the purple (switch 12 volts) is not uncommon. That means the gauge lights come on when the ignition is on. That saves having to have a separate switch for the gauge lights, and with the lamps on, it helps dry out any condensation inside the gauges. If you really want to change the wiring so the gauge lights come on with nav lights, that's not a problem, but I doubt that's your intermittent 'no crank' problem.

When the condition happens, do you lose gauge power? If so (and I suspect it does, due to jumping 12 directly to the purple wire fixes the problem), start looking between the key switch and the point where 12 volts comes from the engine to the instrument harness. Check each and every connection point between the engine and the key switch, including any fuses).

Chris........

 

[Starcraftnewbie]

achris
Sorry working on a 1995 Mercury 60hp 2 stroke. I don’t wanna rewire it. If that’s how it’s suppose to be I’ll leave it. When the engine won’t crank the gauge lights are really dim and gauges don’t work. I can turn the key back and fourth and if the gauges read I know it will start. So you want me to check connections from ignition back to motor? Those connectors are under the dash and look fine. Help me out where I should be looking. As far as fuses they are all brand new and fine too. This buss bar was corroded badly and I replaced it with a circuit breaker with blade fuses. Thank you

 

[achris]

The gauges are going dim because there is a bad connection somewhere. I can't 'help you out' as I'm not there. You have to do the looking and cleaning. All I can say is the problem is that SOMEWHERE is a bad connection. Now that I know what engine it is, I will suggest you remove every electrical connector from the battery to the ignition key and clean them, and don't forget, electricity needs a return path, so do all the negatives too.. That's what I would be doing if I was there. There is no 'magic' I (or anybody else) can perform that will tell you WHICH connection it is, even if I was there. This is what electrical troubleshooting is all about.

Chris......

 

[Starcraftnewbie]

Ok I’ll check out the connectors again. Thank you