by Jon Mikelonis

Introduction
What does adding a stereo amplifier, an electric fan, a tachometer, or any one of a thousand possible mobile electronic devices to your project car have in common? Answer. Almost all of them will call for connection to a "12 Volt Key-On Source" during the install. I can admit that until just a few weeks ago, everytime I read an instruction sheet that declared "...connect the red wire to an available 12 Volt Key-On Source", I cringed knowing that I'd be under the dash contemplating the task. Sure, I could employ the splice technique once again, but something has always seemed inherently lame with the procedure and it usually creates a mess. So, after talking my dilemma over with one more versed in automotive electronics, I discovered a clean and safe solution for creating a block of 12 Volt Key-On sources.

What's Needed?
The slickest part of this homegrown modification is that it can be accomplished with an old Ford starter solenoid. NOT YOUR EXISTING STARTER SOLENOID if you already have one transferring power to your starter. Here's a list of suggested parts, supplies, and special tools. Not all are necessary, but let's do it right.

Ford Starter Solenoid (Relay) If you've ever owned an old Ford, you've seen one of these. If the car you are working on has one, don't get confused, this modification is meant to work with an additional solenoid. The solenoid works as a relay to power a terminal block with 12 Volts supplied directly from the battery. See sidebar for a specialty alternative to using a Ford Starter Solenoid.		Terminal Block Kit (MRG-4455) Mr. Gasket offers these simple but valuable terminal block kits. They come with jumpers, female quick disconnects, male tabs, and mounts for fuses if you need them. The block is designed to handle up to 30 amps. The main supply wire must be fused with a 30 amp fuse maximum. I picked the kit up at Summit.
Inline Fuse Holder This is the fuse holder I used in the main supply wire to the terminal block. They are available at Wal-Mart and most automotive chain stores. I was sure to get one that uses 12 gauge wire.		30 Amp Fuse These standard fuses are also available at Wal-Mart and most automotive chain stores.
12 Gauge Wire This is used to connect the battery to the Ford starter solenoid and Ford starter solenoid to terminal block.		16 Gauge Wire This gauge wire is used to connect one existing 12V Key-On source to the Ford starter solenoid.
Ring Terminal Connectors I needed both large and small ring terminal connectors to use on the Ford starter solenoid. Pictured is a pack for 12 gauge wire (yellow) and one for 16 gauge wire (blue).		Female Terminal Connectors Used to connect accessories to the terminal block. The Mr. Gasket kit includes some but I prefer the fully insulated type shown here.
Firewall Grommet Anytime you pass wire through the firewall, using a grommet is mandatory.		Shrink Tubing Shrink tubing makes terminal connections much cleaner.
Good Ol' Wire Crimps A quality pair of wire crimps beats the ones you always see at the chain store. They made this task much easier.		Drill and Sheetmetal Hole Saw To get through the firewall cleanly, I used a hole saw and power drill.