The National Voltage Star

The wiring of a vehicle is the central nervous system, get it right and you will have a many years of enjoyment, get it wrong and you will not - its that simple. Having said that this is not rocket science, you can wire your car, even if you have never done it before.  People treat this as the last step before upholstery, when in fact it should be a main part of the project planning. Lets face it, you only finish a project when you sale it & wire is relatively cheap, so plan for any electrical items you will add in the next 5 years. Naturally we cant just print money so stay in the budget, but lets say you are going to add a amplifier, or back up camera, or rear speakers, well then it makes sense to wire for them now, you will save a lot of money later because you will not need to remove the interior.Lets back up here and talk about factory wiring, under normal conditions the wiring in a pre-80s vehicle should last about 40 years & 20-30 years for wiring under the hood. If wiring is hard to bend or the insulation is gone it needs to be replaced. Copper wire will get a green tint known as patina, this looks like corrosion but it may not be a bad wire. So if you are on a tight budget it may not be a bad idea to have your stock wiring harness rebuilt, it can even be modified to give you a “plug & play” harness for the modern accessories you are adding. In the mid 80′ the feds mandated that wiring insulation must be biodegradable & the mice love it. Because of this it is very important to tape all wiring that is easy to get to, under the hood is a must trunk is a good idea as well. Completely taping the wires will also give you a clean look as well as protect the wiring, it will not stop a mouse but it may slow them down & it makes it easier to find an damage. So keep mouse traps near your vehicle storage in the winter, just in case.So here are some things to keep in mind about automotive wiring:Ignition systems - most factory wiring & some aftermarket kits have resistor wire or a ballast resistor for the coil. Older coils need 6 volts, newer modern coils & HEI ignitions need 12 volts. If you have HEI or non-stock performance ignitions they should be powered through a relay to provide voltage from the battery or alternator. A stock coil should have a 14 gauge wire & I high power ignition box or an HEI should have a 12 or 10 gauge wire. As with everything else electrical, if you go too small on the wiring the amps will go up & this will add heat, & the heat will damage the wiring. Be sure you have a good ground to make sure you don’t have any noise.Starting and charging - when ever possible use a gear reduction starter, a GR starter can crank over a 12 to 1 compression engine on a hot day with as little as 300 amps & no hot soak. This will take stress out of the battery & wiring. One wire alternators are junk, if you truly have a trailer queen that is always on a battery charger when not in use, then fine use one, but if you plan on driving it don’t. If you are going to have a high end stereo, ac, power windows, or other power hungry devices then don’t use the 10SI alternator (70’s-80’s GM) use a modern one that can provide more power at an idle. But be carful, newer alternators have many possibilities on how they need to be wired up, be sure to get one that matches your wiring & needs. If the battery is in the rear of the vehicle run the correct cable to a junction point or the starter post, this should be the connecting point for the alternator power wire. Be sure to use the correct cable from the alternator & be sure to fuse it. An ignition switch is not a high current connection, it should see no more than 20 amps, got more than that? Then use relays, if you run your entire vehicles power thorough a key switch you will be replacing it quite often or you will have a carbeque, if you do this be sure to have a fire extinguisher handy at all times. Make sure your battery disconnect is capable of handling your vehicles power needs. Do not run starter power through the switch unless you are building a race car or you have a GR starter. I prefer a latching solenoid for a battery disconnect, its just cleaner & pricing has really come down on them but be carful, I have seen some cheap ones in which the contacts burn easily.Audio, video, security, navigation, on board computer - ah the fun stuff. Always run speaker and video wires (RCA cables) at least 1 foot form any power wire, this includes standard (1157) tail lights. If speaker wires and RCA cables must cross power wires do not let them run parallels, it should look like an “x”. Amplifiers need large cables, be sure to match the cable to the power requirements.  Keep this stuff away from ignition components. Most of the items in this category can easily be added later, but anything that runs front to back should be incorporated into the wiring harness, plus this will give it a clean look. Also your alarm can control many things like your shut off solenoid, remote start, trunk pop, windows, door locks, door pop, monitors, motors, & well just about anything you can think of, but again incorporate this into the wiring.Wiring harness - if you are going to wire this your self & it is your first time, use a Ron Frances or a Centech, they are the easiest to understand & the best built / designed. Avoid anything that promises to reduce your pain or make it eazy, they don’t. I say this because of experience, many times the wiring is wrong or not the correct size for the amp ratting of the circuit. The fact is, it’s not very easy to wire a harness that has 3 tach wires & no ignition wires, but that is what I have had to deal with. Most kits are wired for GM (government motors) so you will need to adapt the wiring to work with Ford or Mopar. Soldering the connections is very time consuming, however it is the very best connection, providing you know how to solder, a cold solder will result in high resistance in the connection & that is very bad. Soldering is perhaps overkill for a general use “driver”, it is a must for racing,  motorcycles, and high vibration vehicles such as off road. Here is a tip if you are going to solder the connections, wire the vehicle & do a “soft crimp” on the connectors, once you have everything cut to length and clean looking solder complete harness sections at a time, this will save time as well as keep it clean. If you are going to retain your stock gauge cluster it is a must that you have an accurate wiring diagram, if you cant find one trace the circuit board (60’s up), or the wires on the back of the gauge cluster, keep in mind that the cluster case is usually ground. Get your hands on a wiring socket removal tool and learn how to use it, avoid the round ones that are red and green they are junk and break easily. Don’t give up on the printed circuit board, in most cases we can save ones that are damaged.And finally know your limits - if you buy a good quality harness you will pay $400-$1000 for a universal GM wired or up to $5000 for a concourse reproduction harness. The average labor charge to install a harness is under $1000 some times as low as $300, However show finish will cost extra, its not uncommon for a concourse wiring job to run $8000 to $10000. So if wiring freaks you out have a pro do it. As always we are here to help, need a free bid or evaluation of your stock wiring or if you have questions feel free to contact me Darren@rushps.com or 801-557-7684 but do it quick, if I get any more of this “change”  I am moving to Australia.