Electrical System - Current Affairs

How often have you lamented the passing of the good old days and longed for the era when everything was simple? Take the electrical system in most early cars as an example. They were certainly simple-a starter and generator, a few lights, possibly a radio, and maybe a heater. In most cases, the windshield wipers were operated by vacuum rather than volts, so like we said, things were simple in the good old days. Of course, on the other hand, simplicity certainly has limitations and in some ways, the old days weren't really all that great. Many of the accessories we take for granted today weren't even available back then. But then, in our little universe of street rodding, the forces of old and new collide constantly, and the trick is often knowing how to blend them together and recognizing what compromises have to be made to do it.

A case in point is our Model A pickup. Like many street rods, this one combines a number of elements from both ends of the street rod time continuum. There are lots of traditional touches like a Sharp-equipped Flathead, '50 Mercury transmission, fabricated quick-change, dropped axle and it rolls around on steel wheels with bias-plies and '40 Ford hubcaps. But this A-bone is destined to be a daily driver, so we've also opted to include amenities like air conditioning and heat, halogen headlights, electric wipers, and a few other electron-gobbling devices-let the compromises begin.

We also chose to include a '41 Ford steering column in the mix for a variety of reasons-it had the shifter we needed for our three-speed overdrive gearbox, the LeCarra '40 Ford-style steering wheel we wanted to use fit perfectly, plus there is a built-in ignition switch that also serves as a security device by locking the switch and the steering wheel. And then there was the fact that we've had the thing for years and it was either use it or throw it out.

While we had a list of pros for using our vintage Ford column, there was a big con to overcome, and that was the ignition switch. While it's a cool-looking component, it's probably not adequate for the demands the modern accessories will place on it. We've encountered instances where these switches have been overloaded and as a result were hot to the touch. So the problem was this: We weren't willing to do away with our column-mounted ignition switch and it isn't capable of handling the load that the electrical accessories we deemed necessary would place on it. But that's where street rodding logic comes into play; it's ideal for such a dilemma. We decided to make the electrical system slightly more complicated by adding a relay so we could keep the simple ignition switch.

Basically, a relay is an electrically controlled switch that lets a light-duty circuit control a heavier circuit. The ignition switch will now control a relay in our application, which in turn will control the various circuits.

The first step in our electrical system installation was a trip to our friends at C.W. Moss for N.O.S. internals for our original ignition switch. Even though it won't have to handle much of a load, we wanted it to be in the best condition possible. Next, we got in touch with our buddy Dennis Overholser at Painless Wiring. Along with one of the company's basic eight-circuit wiring harnesses, Dennis sent the relay we needed and supplied the schematic we have included.

While deciding on components for our A's electrical system, we took another departure from the norm with the high-beam switch. In most street rods, including this one, there never seems to be a good spot for the dimmer switch. We had already decided to add an accessory-style turn-signal/four-way flasher switch to the steering column, and as luck would have it, we found one at the local NAPA store that also solved our dimmer switch dilemma. In the end of the turn-signal stalk is the low-/high-beam button that controls, you guessed it, a relay for the headlights.

Another electrical component on the truck that requires a relay is the Flex-a-lite Black Magic engine-cooling fan. However, we don't have to figure out where to put it in this instance because the relay is built in. Also part of the fan's electrical package is an adjustable, temperature-sensitive control that turns it on and off. To energize the fan, we used a single-pole, double-throw switch, which allows for manual or fully automatic operation. This can, however, cause a weird thing to happen in some instances-it may cause the engine to keep running for a short period after the key is turned off with the fan in the manual mode. What happens is this: The fan continues to spin briefly when the engine is shut off; as it does, it acts like a generator and creates a small amount of current, which feeds backward through the system. That current is just enough to make the ignition system function, even though the key is off. When the fan stops, so does the engine. Check out the photos and captions to find the cure.

A final component that requires a relay is an unusual but necessary evil in our situation. Because we made a last-minute decision to add air conditioning, we found it necessary to use a remote condenser that mounts under the pickup bed (we'll show that in detail when we do the A/C installation). Due to its location, a separate electric fan is required, which means one more relay. The relay that controls it-as well as one that controls the fuel pump-mounts under the bed near the battery. This was done to put relays close to the source, so the longest wires are those leading to the switches rather than the heavy wires leading to the loads.

Our intentions here are not to do a wire-by-wire installation of the Painless harness; the instructions included with each kit are clear and concise, so there's no reason to be redundant. And then the nature of building a street rod generally means the layout of components in your car is going to be different than ours. What we are going to do is concentrate on how and why relays may play a part in your rod's electrical system, toss in a few tips on installing the necessary components and running the wiring, and show a few custom touches we added to our A while we're at it. Nothing shocking about all that, is there?

Old-Style IgnitionIt's often said that "there's more than one way to skin a cat." And while we've never tried that one way or another to know for sure, we can say with certainty that there's more than one way to wire an old Ford and retain the original ignition switch. Here's another method to consider.

Electrical systems and switches are always a challenge when trying to keep the original look. Converting from six-volt systems to 12-volt has become common, but sometimes the original switches can be tricky to use. The original ignition switch, like the one in this 1939 Ford, will not carry the amount of current required by today's creature comforts, and it has segregated circuits for ignition and accessories. These switches can still be used by incorporating some relays to create separate circuits for ignition and accessory devices.

The starter is another item that can be a challenge. The original six-volt starter solenoid used a ground to activate it where most new 12-volt solenoids require a 12-volt input for activation. Once again, by using a relay, the original starter button, which creates a ground when depressed, can be used to trigger a 12-volt activation input to the starter solenoid.

Old-style looks will always be in demand; all we have to do is figure out how to keep them and still have the creature comforts to which we have become accustomed. Here's another way to do it.