Of course you can. "You can do it...we can help"

Once you get into it and figure out what you're looking at, eliminate all the junk that goes to nowhere, and start hooking up your new stuff it really isn't that bad. Be sure to spend a few extra bucks and take your time and do it right. It will pay off in the end. Also remember, K.I.S.S. Don't make the new system more complicated than it needs to be, you want to be able to look at it and know what it is if you ever have to make a repair.

And use marine grade heat shrink, marine grade tinned wire, and marine connectors. Keeping saltwater out of the wire and connectors goes a LONG way to making the wires last. It doesn't take but a few hours of electrolisis affecting copper wire to turn it black and cut down it's ability to conduct electricity. Pay a little more now, or pay a lot more in a short time to redo it. This is a lesson I have learned the hard(and expensive) way.

:oh:

Now, y'all hipped me to getting tinned wire...but marine grade heat shrink? I didn't know there was such a thing. Now I know!

And I went to Radio Shack (going out of business sale) and bought some regular heat shrink connectors. Oh well, I can use them for something else.

good place 4 wire http://www.bestboatwire.com/

i've used the regular heatshrink and just put a shot of dielectric grease in it. seems to hold up pretty well.

Marine heat shrink has a sealer inside of it. When it is heated to shrink it, the inner liner turns to glue to completely seal the connection. It is some GOOD stuff, but hang on when you see the price. I remember buying it for $.25 a piece, and the last ones I bought 2 years ago were about $2 a piece. The problem I have found with the heat shring terminals is when you crimp them, you normally pierce the heat shring and leave part of the terminal exposed where the elements can get in. They're still good conenctors, just be careful crimping them. For your main feed wires, make sure and crimp, solder, and heat shrink them. If you crimp then solder the ends, it can still conduct electricity even if somehow you get a bad spot i nthe wire and it starts to turn black. If you just crimp it, that black portion inside the terminal wil lstop electricity from conducting, but when you solder it the black eelctrolisis cannot happen so the wire lasts longer(if that makes any sense, I'm pretty bad at describing things).

By the way, I've had good results with Harbor Freight heat shrink connectors. They have the glue in them also, and make a perfect seal.
Additionally, remember that liquid electrical tape is your best friend. As the name implies it's a non-conducting liquid that you can brush on any electrical connection. After it dries you have a 100% complete air and water tight seal. I pretty much use it for any connection I have to make, including covering the spade terminals where they go into the buss box.
Remember, you're not only trying to keep out any water, but also any air. Salt air is just as corrosive as salt water. It just takes a little longer, but the result is the same. So make those connections as airtight as possible.

I do have a fuel gauge (that I thought I had to replace...'nother story, 'nother thread), and it seems like it's grounded to a switch. Can you please shed some light as to why it would be and why it needs to be on a switch?

UPDATE:

I'm slowing, but surely working my way through it. I have discovered an additional bus bar that must be the original, and it is buried behind a tangle and does have heat coming to it....sigh.

The majority of the switches on that dash have been disconnected...no wonder why nothing works. As you can see in the earlier picture, there is a sad little wire harness that's running loose.

Also, my stern bilge pump (Sahara S750) isn't getting any heat, evidenced by the test knob that I turned. It may need to be replaced, as it was sitting in a block of ice a couple of days ago, and is now sitting in the middle of gunk.

I also second on the K.I.S.S method... I've got a complete re-wire project coming up on mine. I've got a few plans to run a dual battery system with a Automatic Charging Relay installed between the start battery and the house. Blue Sea Systems makes a really nice kit.

My thought on running a dual bilge pump system. Make sure that you run two separate switches/powersource for those. Just in case one pump goes, blows the fuse, etc... that way you have a way of running the back up one. There is nothing like trying to troubleshoot a blown fuse in an emergency.