On the 110 V side of the harness it consists of a salvaged AC male plug from a computer power supply, a simple rocker switch with an on / off position and a 110 V indicator light. I incorporated a 40 amp fuse in the positive lead to the power supply and ran the negative and ground leads out to the power supply. Because there was the indicator light small leads for the positive and negative were tied into the main leads after the fuse.
How it works ...
When the power supply is mounted the switch on the power supply is turned on, connected to the power supply is a female end of a computer power supply cord (same as the cord for the power supply) that connects to the light and switch. Power is controlled by the rocker switch on the instrument panel. When the switch is in the on position the red indicator light illuminates and the power supply comes on. When the switch is in the off position the indicator light turns off and the power supply turns off.
The Wire Harness hooked up and marked
In the radio box I am using a PowerGate, this connects to the output of the power supply via a Anderson power pole connector to the "PS" side of the PowerGate. The dual Anderson power pole pigtail connects to the "Output" of the PowerGate and the external Anderson power pole plugs mounted on the instrument panel connect to the "Battery" side of the PowerGate. This way when the power supply is unable to provide power the battery will take over and still power everything, except the red AC indicator light.
A view of the PowerGate with everything but the battery hooked up.
I've not made the part of the 12 V harness that connects in the battery because I've just ordered the mounting plate for the Anderson power pole connectors on the instrument panel. The mounting plate will house a double connector, which will provide for a Anderson power pole out connector on the panel. On the power supply output to the PowerGate, I need to incorporate a fuse in the positive lead, once that is done that part of the harness will be done.
When tested today before the power starting to surge and go out, everything worked as expected and I am relatively pleased with it and the wire management of the harness is good that it is not a rat nest of wires and the air flow is not impeded by a mess of wires.
Edited October 30, 2012:
Today I got the sheet metal required to build the panel on the bottom / top inside of the internal rack. This allowed me to mount the power supply and PowerGate. Mounting the power supply was a bit tricky because I wanted the ability to remove it should it ever need to be replaced in the future. I took a L bracket and cut off part of one end so it was at the top of the power supply, the other end I left alone and bolted it to the sheet metal.
There is a short bolt that goes into the power supply (head is inside with a nut) it is feed through a hole in the L bracket and another nut is tightened to secure the power supply to the bracket. What you don't see in that photo is the quick tie that holds the other end in. I drilled a hole near the other side of the power supply put a rubber grommet into the sheet metal and ran a very long quick tie into another very long quick tie and locked the quick ties down tight against the power supply and then trimmed. Also had to make sure none of the locks would interfere with the rack sliding in and out of the case.