Overheat Alarm. 1998 Bayliner Trophy w/120HP Mercury Force

[Themanofsteel]

So I have a bit of a puzzle to solve. I recently purchased a 1998 Trophy. The Overheat alarm was not working. After doing several tests I concluded that neither the engine sensor nor the positive was reaching the alarm. The alarm speaker had a Purple and Tan/Gray Strip wire connected to it. Both wires go to the engine.

When I looked at the heat sensor on the engine, its was connected to a solid tan wire. I found the tan/gray strip wire and connected it to that instead and was able to trigger the alarm.

The purple wire was not connected to anything. In fact it was capped off with nowhere to connect it to. See Photos.
I temporary connected it to the positive on the battery and the alarm works but there is no place on the engine to connect the purple wire. It's bunched up and wrapped with a bunch of other wires.

Where should I connect it to and out of curiosity, what is the tan wire and why might have the overheat sensor been connected there?

 

[jerryjerry05]

Mercury uses a tan wire for the over heating system.
Force up till the mid 90's used an orange lead.
Purple is usually a 12v power lead(I think) Does it look like the factory taped it or the owner?

 

[Themanofsteel]

The Tan-Gray wire is connected to the Alarm so I was curious what the solid Tan wire was. But since the Tan wire goes nowhere I figured out the sensor needed to be connected to the Tan-Gray wire.

It looks like the end of the purple wire was capped off with a rubber plug. And it has no where to plug in. All the wires are grouped together with a plastic shield that looks original and are secured to the engine with zip ties.

​​​​​​​see photos.

 

[Themanofsteel]

Question: Why would the purple wire need to go all the way to the engine? Why wouldn’t they just connect it directly to the positive behind the dashboard and to the alarm also behind the dashboard.

 

[jerryjerry05]

That would be a question for the factory??

 

[Themanofsteel]

jerryjerry05 Thanks. Since the purple isn’t connected to anything I connected the alarm speaker to the positive behind the dashboard. It’s all working now. I’m just still bothered by solid tan wire and why the purple wire has nothing to connect to.