Automotive wiring 101
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| + | ==Preamble== | ||
| + | This article is a comprehensive guide for automotive wiring and will take you through all aspects of the parts, equipment and the knowledge required to wire and run all accessories in modern automobiles. | ||
| + | ==Wire== | ||
| − | + | [[File:Roll_of_wire.jpg]] | |
| − | + | ===Types of wires/applications=== | |
| − | + | *[http://www.wirebarn.com/Wire-Selection-Guide-_ep_29.html Wire Selection Guide] | |
| − | + | ====Copper==== | |
| − | + | ====Aluminum==== | |
| − | + | =====Stranding===== | |
| + | The type of wire stranding is important when it comes to the maximum load capacity of a wire. With DC current, the more strands in a gauge of wiring the better it can carry the load without overheating and failing. Compare a lower grade of wire made of 19 strands of individual 21 gauge wire wound to form a 8 gauge wire, to the wire shown below, that is made up of 133 strands of 29 gauge wires to form the same 8 gauge wire. | ||
| − | [[ | + | [[File:Strand_comparison.jpg]] |
| − | + | ====Insulation/covering==== | |
| − | + | ====Ratings==== | |
| + | *[http://www.wirebarn.com/Wire-Calculator_ep_41.html Wire Size Calculators] | ||
| − | 2. | + | *[http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=2.061&voltage=13.8&phase=dc&noofconductor=1&distance=10&distanceunit=feet&eres=23&x=55&y=16 Voltage Drop Calculator] |
| + | ==Tools== | ||
| − | [[ | + | {| |
| + | |[[File:SOLDERING EQUIPMENT 001.jpg|thumb|center|350px|Selection of soldering equipment: Various soldering irons and gun, rosin flux, solder, desoldering supplies]] | ||
| + | |[[File:TERMINAL AND WIRE STRIPPER TOOLS 002.jpg|thumb|center|410px|Terminal crimping and wire stripping tools]] | ||
| + | |} | ||
| − | + | ==Terminals and connectors== | |
| − | + | ===OEM terminals and connectors=== | |
| + | OEM type hardware can be sourced from a junkyard. Use proper splicing techniques if going this route. | ||
| − | [ | + | These OEM connectors are also available in the aftermarket. One such place is [http://www.repairconnector.com/ The Repair Connector Store] |
| + | |||
| + | ===Crimped type=== | ||
| − | [[ | + | [[File:Wire_connector.jpg]] [[File:Multiple_wire_connector.jpg]] |
| − | + | The crimped type terminal/connector is the most common type of connector in use in automotive wiring. They come in several different sizes to fit a given range of wire gauge size. The wire is slid into the connector and a wire crimper mechanically binds the wire to the connector by compressing a divot in the holder. Some connectors use a plastic skirt that insulates the wire/connector from shorting and the color identifies the average wire gauge (awg) to the user. Terminals/connectors are available in a wide array of styles from spade, bullet, butt, ring, etc. | |
| − | + | These crimp-on types also are ganged together inside multiple holders or "terminal blocks" to form the basis for wiring circuits and harnesses used in automotive applications. | |
| − | [[ | + | ===Screw-on type=== |
| + | Screw-on type connectors are a compression type of connector whereby wire(s) are inserted in a insulated sleeve and a compression cap is screwed tight to lock in the wire to the sleeve to make a tight- and in some cases water resistant- connection. | ||
| + | |||
| + | ===Battery terminals=== | ||
| + | [[File:Bad batt clamp term.jpg|thumb|220px|left|Clamp-on replacement battery terminals are to be avoided!]]Do not be tempted to save money by using one (or more) of the cheap, clamp-on style battery cable terminals. Even if they are tight and look fine, all too often they will cause high resistance and can make it seem like the battery is bad, etc. If the terminal fails on a cable there are better terminals that may be used to replace them, or the entire cable can be replaced with a cable having a larger diameter and quality terminals already installed. | ||
| + | <br style="clear:both"/> | ||
| + | ==Fuses / Circuit breakers== | ||
| − | + | [[File:Fuse.jpg]] | |
| + | ===Fuse panels=== | ||
| − | 4. ''' | + | ==Switches / Relays / Sockets== |
| + | |||
| + | *[http://www.colehersee.com/home/catalogs/ Catalogs] | ||
| + | |||
| + | ==Circuits== | ||
| + | |||
| + | Individual circuits fall into one or more of the following categories: | ||
| + | |||
| + | 1. Branch circuits. These supply power to a single device or system. This will be most of your harness (but not all) and includes most of what everyone thinks of when you say 'wiring'. | ||
| + | |||
| + | 2. Feeder circuits. These supply power to multiple branch circuits and/or have combined loads on them. These can include the wiring from your battery to a fuse panel or a switch, or the power wire out of your generator/alternator to the battery. These can also be a power wire supplying a circuit that has multiple devices/loads connected to it. | ||
| + | |||
| + | 3. Continuous loads. These are all the circuits that if you turn them on, can be on for an extended period or will be on anytime the vehicle is running; most lights, ignition, radio, heater, and so forth. | ||
| + | |||
| + | 4. Intermittent loads. This will generally be power accessories like power windows, locks, seats, etc but can include any load that will be usually on for short periods of time (like under one minute). | ||
| + | |||
| + | A feeder circuit will almost always be a continuous load, but a branch circuit could be either. The reason for splitting the branch circuits into two types is so we can apply a concept known as 'diversity' when figuring feeder loads. This is based on the idea that not everything will be operating at once. | ||
| + | |||
| + | |||
| + | Before you start running circuits, it is best to know how much amperage each one of those accessories will take to power it up. Keep in mind there are four types of accessories we will be dealing with; un-switched continuous, un-switched intermittent, switched continuous, and switched intermittent. | ||
| + | |||
| + | To follow this through, let’s look at a typical 1960/70 automobile and see what kind of amperage we are dealing with and how they relate to the design of an automotive electrical system: | ||
| + | |||
| + | |||
| + | |||
| + | 1. Headlights. There’s four, and when on high beam the 'typical' amps each is 5A for a total of 20A. | ||
| + | |||
| + | 2. Taillights. There’s four and at .7 amps each , plus the license plate light, =3.5A. | ||
| + | |||
| + | 3. Brake lights. Four @ 2.25 each, = 9A. | ||
| + | |||
| + | 4. Dash lights. Four @ .3A each, =1.2A. | ||
| + | |||
| + | 5. Emergency flashers. When your flashing, the four brake lights at 2.25A each, two dash indicator lights at .3A each, plus front turn lights at 2.25 each, =14.1A. | ||
| + | |||
| + | 6. Interior lights. One overhead light and two door sill lights, =1.8A. | ||
| + | |||
| + | 7. Back-up lights. Two at 2.25A, =4.5A. | ||
| + | |||
| + | 8. Lighter. 16A if you actually have a lighter, even if used as a power-point, = 16A | ||
| + | |||
| + | 9. Horns. Two at 6A each, =12A. | ||
| + | |||
| + | These add a total of 82.1 amps. These are not all continuous, so you don't need 81 amps all the time. Your continuous loads are only items 1, 2, and 4 as a general rule, so the continuous load is only 35.5 amps, less than half. | ||
| + | |||
| + | To calculate for switched circuits: | ||
| + | 1. Ignition, 12A. | ||
| + | |||
| + | 2. Wipers, 6A. | ||
| + | |||
| + | 3. Turn signals, 7A. | ||
| + | |||
| + | 4. Heater/AC, 24A. | ||
| + | |||
| + | 5. Gauges, 4A. | ||
| + | |||
| + | 6. Radio, 7A. | ||
| + | |||
| + | 7. Power seat, 16A. | ||
| + | |||
| + | 8. Power windows, 16A. | ||
| + | |||
| + | The total load equals 92 amps, but your continuous load is lower. Items 1, 2, 4, 5, 6 are continuous and total 53 amps. | ||
| + | |||
| + | Just adding up 'basic' continuous loads (35.5 and 53), equals 88.5 amps for total continuous load. This number represents how many amps your charging system needs to put out just to stay even, so as not to create a draw on your reserve, the battery. Normally, for sizing the charging system, the intermittent loads won't count; you draw off the battery and then the charging system will replace the power as you drive. | ||
| + | |||
| + | As you advance your ride with the latest electronic features, you have to take into account the extra power that the electrical system must generate to keep up with your accessories. Perhaps, that new electric fuel pump and twin fan setup will become the cause of the dreaded ‘Dead Battery Syndrome’ that is plaguing the automotive scene today. The old 63 amp GM alternator will be tossed for a 140 or even 200 amp alternator in order to run that giga watt stereo system that you’re cruising with today. Do your homework and build your electrical system right! | ||
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| + | |||
| + | ===Grounding=== | ||
| + | Many of the functions on a vehicle are electrical, which requires a way for the current to get from the battery to the load and then another way for it to get from the load back to the battery. Often times, fellows will be chasing around trying to find a problem when the real problem is the lack of proper grounding in the vehicle. | ||
| + | |||
| + | A framed car gets a line from the negative battery terminal to the motor, motor to frame and frame to body (3 separate cables). A unibody car gets a line from the negative battery to the motor and motor to body (2 separate cables). | ||
| + | |||
| + | Ground cables can be made from #4 battery cable (see your nearest welding supply store). Welding cable will carry much more current for the same size because the wire strands are much smaller inside the cable than the cheap cable from Auto Zone, etc. Cut the cable to length then sweat on copper lugs and cover them with heat shrink tubing. | ||
| + | |||
| + | *Battery negative to motor: There will almost always be a threaded hole somewhere on the block or head. If not, use a bolt that holds something else and is handy. Run a finishing tap down to the bottom of the hole and blow out the chips and other crud in the hole by spraying carb cleaner into the hole with the little red straw that comes with the can. Watch your eyes and do not breathe the vapor. Now, use a file or your pocket knife or other suitable tool to scrape off all crud, paint, rust, etc. from around the hole. You want the lug laying against bare metal when you tighten the bolt down. Cover the entire connection with clear silicone so that no moisture can get into it. | ||
| + | |||
| + | *Motor to frame: Same way, but with a plain lug on each end of the cable. If there is not hole in the frame to use that's convenient, drill the proper size hole for a self-threading bolt. Make sure there are no fluid or electrical lines running inside the framerail that would be breached by drilling a hole. You don't have to push the drill bit all the way in, just stop when you feel the bit clear the metal on the other side of the rail. Use a file or knife or sandpaper to make a large, clean, bare spot of shiny metal to attach your lug to, then seal it as above. | ||
| + | |||
| + | *Motor to body or frame to body: Find a place on the firewall where there is already a hole that you will have access to from the outside and from the inside of the car. If there is not one available, then look around for a good spot. You will want a spot on the inside where you can get to it with a socket or wrench to hold a bolt head. We're going to use a bolt and nut and maybe a couple of washers for this one. On the motor side, clean off an area down to bare, shiny metal where the lug will sit so that the lug will not be sitting on any painted part of the firewall. Run the bolt into the hole from inside the car and have a buddy attach the ground cable/washer/nut and tighten it while you hold the bolt head from inside. Once tightened, cover the connection thoroughly on the inside and the outside with clear silicone. | ||
| + | |||
| + | ===Battery=== | ||
| + | |||
| + | [[File:12_volt_battery.jpg]] | ||
| + | |||
| + | Batteries come in a wide array of of case sizes, amperages, and post arrangements. Choices of side or top post include at least 12 to 15 different case sizes, as well as more than 10 different amperage's to suit any given application. Automotive batteries are available as wet-cell, gel-cell, or AGM (absorbed glass mat) types. | ||
| + | |||
| + | See: [[Auto battery]] for more. | ||
| + | |||
| + | ===Alternators=== | ||
| + | See: [[Troubleshooting alternators]] for more. | ||
| + | |||
| + | ===Starters=== | ||
| + | See: [[Starter motors]] for more. | ||
| + | |||
| + | ===Suppliers=== | ||
| + | *[http://www.keepitcleanwiring.com Cloth Wrapped Wire Harness Kits] | ||
| + | *[http://www.johnnylawmotors.com Wire Kits] | ||
| + | |||
| + | ==Resources== | ||
| + | *[http://www.danielsternlighting.com/home.html Daniel Stern's excellent page on headlight relays, voltage drop, etc.] | ||
| + | *[http://www.archtoolbox.com/representation/abbreviations/99-electabbrev.html Electrical abbreviations] from archtoolbox.com | ||
| + | *[http://www.vernco.com/Sparks/id606.htm Voltage drop test] | ||
| + | |||
| + | *Crankshaft Coalition wiki articles: | ||
| + | **[[How to solder electrical connections]] | ||
| + | **[[Troubleshooting electrical problems]] | ||
| + | **[[Understanding the math of electrical loads]] | ||
| + | **[[Wiring diagrams]] | ||
| + | **[[Remote Ford solenoid for GM- no hot start]] | ||
| + | **[[Relay application guide]] | ||
| + | **[[How to solder electrical connections]] | ||
| + | |||
| + | [[Category:Electrical]] | ||
| + | [[Category:Ignition]] | ||
| + | [[Category:Undeveloped articles]] | ||
| + | [[Category:Undeveloped Electrical articles]] | ||
| + | [[Category:Undeveloped Ignition articles]] | ||
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