There are 2 advantages to having the port in my doghouse:
1. My phone usually rests on top of the doghouse while I'm driving so the wire doesn't need to stretch across the cab from the dash creating clutter.
2. It is very easy to tap into the hot lead from the horn relay, or other power source, to power the plug... and the dog house is already grounded so the ground ring doesn't need a wire.
I made it at Tech Shop where I first discovered the beauty of the Step Bit . http://www.techshop.ws/
They have a fantastic collection of useful tools. Here's what you will need
0. Auto Powerport / Cigarette Lighter Assembly
1. Step Bit
2. Power Drill
3. Soldering Iron & Solder
4. 14 - 18 Gauge wire
Lets get started...
Step 1: Drill a Pilot Hole or Use Existing Hole
Go to an auto parts store and find a good metal power port or cigar lighter assembly. It might include a metal ring for mounting under the dash. I tried it that way for a while but I don't like how it looks with the exposed wires and the port hanging down. My dash is too beautiful for that. ;) You can unscrew the two halves and remove the mounting ring if necessary so that it will fit into the hole we will make in the doghouse.
Step 2: Increase the Hole Diameter With a Step Bit
Step 3: Solder the Hot Lead
Step 4: Ground Ring Wire
Step 5: Wiring It Up
Step 6: Connect to Horn Relay Hot Wire
Step 7: Finished
Charge up your 21st Century gadgets in your Mid 20th Century van.