Help with ?'s
 

I'm working on a friends boat and I have a couple questions if someone could please help us out.

In one picture I have two water temperature senders, one switch for alarm and one sender for gauge. Which one is which?

Second picture is his alternator. Anyone have a wiring diagram? When he pulled it from engine he pulled all wires out of their connections. So I just want to make sure I get it correct going back together. Also what is that little box laying on the floor? I looked and asked all over, no body knows. The black wire coming out of it goes to the black wire of the alternator and we have no idea where the this red wire goes. Is this for noise? and where does it bolt up? it has two mounting holes in its bracket not shown in the pics but the owner doesn't remember unbolting it.

Thanks for the help... Anthony

The longer one is for the alarm like this,
http://www.wholesalemarine.com/p/48952/
or item #1
http://www.mercruiserparts.com/Show_...WARNING+SYSTEM

What year & engine model are you working on? Engine serial number handy?

It's a 1994 merc mag 454. No numbers handy right now.

You will want to find your Ignition Module on either page 4F-2, 3 or 4 for the correct electrical system diagram,
http://www.boatfix.com/merc/Servmanl/16/16F4R2.PDF

Alternator system,
http://www.boatfix.com/merc/Servmanl/16/16C4R2.PDF

Anyone have any idea what the box is laying on the floor in front of the alternator in pic 2? Its grounded to alternator and then a red wire sticking out. No idea what this is or where is was mounted...help

Thanks for all the help so far. All my other questions where answered. Anthony