Motor starts but gauges stopped working

[Mgm2617]

I have a 1993 Nitro 170 DC with a 115hp Johnson on it. Boat runs great and everything has always worked but all of a sudden all of my gauges stopped working and there is a constant tone from the alarm warning when you turn the key to on position. The motor still cranks and starts like it always has. Could this be an ignition switch problem?? I went through the motor and tried troubleshooting the alarm by disconnecting one thing at a time and I couldn't get the alarm to stop. Can someone please help?? I am out of ideas!

 

[alldodge]

Need to get a volt meter and see if your getting 12V at the gauges.

 

[Silvertip]

Not an engine wiring issue. Gauges are powered from the "A" terminal on the ignition switch. Lack of +12 volts or ground on first gauge in the string will kill all of them.

 

[Mgm2617]

So it more than likely has to do with the ignition switch or a ground connected to the ignition switch?

 

[alldodge]

So it more than likely has to do with the ignition switch or a ground connected to the ignition switch?

Most likely, terminal A powers up everything, and since you have an alarm going off, there is power to terminal A. This also means you have a ground being applied to the alarm circuit since the alarm is on

 

[Mgm2617]

Thanks for the info guys, I appreciate it!

 

[Mgm2617]

Okay so changed the ignition switch. Gauges now working and back to normal but I still am getting the constant tone from the warning horn when the key is turned to on. I don't think it's a faulty horn?

 

[alldodge]

Okay so changed the ignition switch. Gauges now working and back to normal but I still am getting the constant tone from the warning horn when the key is turned to on. I don't think it's a faulty horn?

Being an OB I'm not the best guy, but the alarm sounds off for things like, over heat, low oil pressure (4 stroke), low oil injection tank (2 stroke). Find the items and start pulling the wires off the sensors, one at a time

 

[Mgm2617]

I've now taken apart every connection I could find and the alarm stayed on. Traced the tan wire back to the motor and it is wrapped in rubber so it's not grounded. I have no idea what could be causing this!

 

[alldodge]

Disconnect the Tan wire from the alarm, if it goes out you have a short in the wiring, if it doesn't your alarm is bad