Chris, as I recall the old and new connectors were different shape and the wires were in different locations in the plugs. There was also different color coding on the wires. The new head unit will have a wiring diagram in the installation instructions. The Four Winns website has the owner's manual (
http://www.fourwinns.com/customer-servi ... nuals.aspx) with wiring schematics at the end of the manual. The color codes for the stereo wiring can be found there.
You can:
1. Cut the old harness off the old head unit and splice the old harness on to the new head unit. This leaves the original boat wiring intact.
2. Cut the boat's wiring harness after the connector and splice there. This leaves the new head unit wiring intact but the boat's wiring is modified.
3. Cut the old harness off of the old head unit and splice it to the new harness after the plug. This means that the audio signal goes from the head unit through the new connector, then the old connector, then to the speakers. You can make this adapter harness and it is pretty much a "plug and play". You may still have to make the power or other connections. I recommend this method because the old head unit is inop anyway, and it means less splicing in the boat's harness.
The current head unit has has 4 screws holding the mounting plate to the panel. There is plenty of length in the wiring harness, You can lay a folded beach towel on the galley counter top and lay the old or new head unit on the counter top to work on it. The new mounting bracket for a standard DIN size head unit like your old unit or my new unit will fit in the current mounting plate. If you decide to go with a larger (double DIN) unit you will need to get a different mounting plate and possibly open up the hole in the wall.
Hope this helps. Gary