Electronics Article

From 3.8Wiki

Introduction

Welcome to the new Electronics Tech. This is the updated version of my original wiring tech article. I wrote this to help out those that needed assistance when it came to dealing with wiring in extra accessories or troubleshooting pesky electrical problems. Feel free to download and save all the diagrams that you want, but do not duplicate my work without my permission. You will find various terms throughout the article that you may not know. If the word is in purple, then the definition is located in section 10. If you have questions regarding the content or want to contribute information, please send me a PM or email me at majikman001@yahoo.com. I hope that you find this thread helpful. Happy wiring!

Safety

Remember that you can be severely injured while working on the electrical system of your car. Disconnect the battery and press your brake pedal to dissipate the remaining power. Never work in the vicinity of the airbags or the airbag sensors when they have power as a slight jolt could possibly set them off. Do not just go probing live wires without knowing what they go to. Failure to do so may result in a shock or electrical wire at worst. Do not let live power wires touch a ground; doing so may also blow fuses or short out circuits and extended contact will cause the wires to heat up and the insulation around them to melt, creating a fire hazard.

Fuse Diagrams & Wire Schematics

Located in our Fuse_and_Wiring_Diagrams section.

Basics

Wires

As you know, there are various types of wires. They consist of different cores, and types of insulation. In this article, we will focus on the most common wire used in auto wiring (copper core / rubber insulation). There are different sizes that are defined by their gauge. Contrary to what you might think, the smaller the gauge, the larger the wire.

Wire Types

Colors

• 14 to 18 gauge is the typical size for wiring neons, fogs, LEDs, etc.

• 8 to 10 gauge is more along the lines for wiring the cooling fan or an amp.

• Color abbreviations is generally standardized, but you may come across many variations.

Resistance

This is the current limitation of a wire. The power dissipated in wire will be in the form of heat. The higher the resistance, the higher the heat dissipation will be in a smaller wire. If the wire is too small and the current too great, the wire will become too hot, the insulation will begin to melt, and you have a potential fire hazard on you hands.

Wiring

Splice & Twist

This is by far, the most commonly used technique. There is nothing wrong with it, as long as all connections are insulated by electrical tape to prevent shorts and corrosion. Cut the wires to be connected together and remove some of the insulation from the ends, bring the two ends together, and twist the wires tightly to make a good connection that won't easily separate. Next, wrap the exposed wiring with electrical tape, making sure that no wire core is left exposed.

Pre-formed Taps

A small plastic wire tap that allows the tapping of one wire into another without cutting. You simply place the wire you want to tap in one side, the tapping wire on the other, and squeeze the tap together with pliers. It does this by making a very thin cut in the main wire's insulation and simultaneously doing the same to the other wire when the tap is closed. Extra insulation is not needed unless it is exposed to the weather.

Splicing & Wrapping the Wire

Another way to splice is to remove some insulation from the wire you want to tap, and then wrapping the exposed end of the tapping wire around the exposed core on the tap wire. This is not the best way, but works fine. Remember to cover it with electrical tape or another type of insulation.

Solderless connectors

Solderless Butts & Other Connectors

Various connectors are used for connecting wires together. Solderless butts are connectors where the exposed core of wires can be pushed in and crimped with wire crimpers. This is one of my personal favorite methods as you can get many different kinds and sizes at a local auto or electronics store.

Wire Crimpers

These are used for crimping solderless connectors. you can find them at any parts, hardware, or electronics store. They also double as wire cutters and strippers. To use the stripper feature, place the wire in the indention that is the same gauge as the wire you want to strip. Then, close the crimpers and pull off the insulation.

Soldering

Soldering Iron

This is the best method for electrical connections by far, but requires much more experience than simple cutting and taping. Soldering can provide a strong or weak connection, depending on the way it's done. Soldering is done by melting a soft metal called solder, and using it to "fuse" connections. It provides a long lasting and highly conductive connection, but should be covered with a insulation material once it's done, preferably a silicon coating if possible.

• Soldering Iron / Soldering Gun

Used to melt the solder. They are most commonly found in a "gun" shape (L shaped), or in a iron shape (straight). They vary in wattage (heat range). The tip is replaceable and should be when it begins to lose it's heating ability in the very end of the tip.

• Rosin Core (non-acid) Solder

This is the solder type used for electrical connection soldering. It comes in various sizes to meet you needs.

• Acid Core Solder

This is used for non-electrical connections, such as connecting regular metal. It comes in various sizes to meet your needs.

CAUTION

Do not solder until you practice. You can mess up wires, connections, plastics, or even seriously burn yourself. Please use with caution - it is not for beginners.

Proper Insulation

Heat Shrink

Heat shrink is a special plastic that shrinks when heat is applied to it. This is used to created water proof insulation. Use this whenever the connection may be exposed to the elements to prevent corrosion or shorting.

Cold Shrink

Coldshrink is a special tape that sticks and conforms to itself to create waterproof insulation. You can see examples of this on your car by looking at some of the factory wiring for your stereo or taillights.

Silicone/Teflon Coating

Another type of insulation, a silicone or Teflon coating will create a waterproof seal around anything it's sprayed on. This is useful for protecting circuits and other vital connections.

Dielectric Grease

This is a special grease that should be used if it's on a place where being able to disconnect is important. This grease prevents corrosion and seizure of the connection. Use this on any harnesses/plug in connectors for easier maintenance and repair.

Hiding Wires and Extra Consideration

Wire Loom & Other Tricks

Wire loom is a type of plastic accordion tube used to protect wires from various elements and conditions, as well as group specific wires together. They come in a variety of sizes and colors. Another trick for hiding wires is to place them behind panels or under carpet. Running them under the door sills is a great way to get speaker wires to the rear. Running wires up the A-pillar is a good way to hardwire a radar detector above the mirror. Wire ties can also greatly help. Use them to keep wires together and/or to hang/support them. They also come in a variety or color and sizes.

Environment Consideration

Another thing to consideration when picking which technique and materials to use is the environmental conditions. Is the temperature going to be extreme, hot or cold? Will it be sitting in or near and come in contact with oil, grease or solvents? You have to consider all these things when wiring to prevent headaches or electrical damage later. If the wire(s) will face weather such as rain, I would highly advise using heat shrink or cold shrink tape on all connections, taps, splices, etc.

Failsafe Protection

Fuses

Fuses

Fuses come in a variety of shapes and amperage ratings and prevent damage from too much electrical current by blowing when it surpassing it's rated ampere. This is a very important safety device that can prevent damage that can range from a blown cigarette socket to a fire under the dash. They are cheap insurance and should be used whenever possible.

Let's imagine a piece of wire has .01 ohms of resistance (~8 gauge wire & 12-14 ft) and that wire is connected directly to the (+) of the battery (without a fuse). Now let's say that the other end of the wire is accidentally touches to the chassis of the vehicle (which is (-) in most vehicles). The two terminals are basically shorted together by the wire. In this case, a very large amount of current will flow through the piece of wire.

Now, lets figure out the current flow through the wire, using Ohm's law formula I=E/R. Take the battery (12 volts), divide it by the resistance of the wire (.01 ohms). We get a current of 1200 amps.

I = E/R

I = 12/0.01

I = 1200 amps

Then plug the current into the formula P=I2*R. We get:

P = I2*R

P = (1200*1200)*0.01

P = 14,400 Watts!!

This calculation shows the wire would now be trying to dissipate 14,400 watts of heat. This, in turn, would melt the wire's insulation and more than likely begin to destroy or ignite everything that comes in contact with the wire (other wires, carpet, plastic, insulation). Obviously, if you are tapping off of an existing wire (not wiring directly to the battery), more than likely, you are already on a line with a fuse. But, it would be safe to wire in an additional fuse (especially if you are on a line with a 20amp fuse and the ideal should be 10amp. You don't want to destroy your wiring. I've seen it before, and it's not pretty.

Ever rewire the dash on a 89 Dodge?

Circuit Breakers

Circuit breakers are similar to fuses in their function. They prevent current higher than their rating from flowing through. The major difference being that instead of blowing, like fuses, they trip (or open their connection), preventing the current from going through. Some reset on their own once the current has returned to an acceptable level while others have a switch or lever to reset them (a good example would be the circuit breaker in your house). These do not last forever, however, and will eventually wear out, although the common circuit breaker in a car will usually still be working by the time the car has died.

Relays

Relays allow you to use a very small amount of power from a tapped source to trigger a relay to pull power from the battery (or other big power source) to essentially link it to the item that needs power.

12v Relay

Think of it like this:

pin 86 - GROUND

pin 30 - POWER SOURCE

pin 85 - TRIGGER

pin 87 - OUTPUT

pin 87a - OUTPUT (Always on) *only on 5-pin relays

switch-side1 (pin 85)

switch-side2 (remote power source - tap into a positive power source)

When you turn on the switch, the little amount of power will trigger the relay to close it's gate, enabling power directly from the battery to run through the gate and to the item that needs power. Thus, you use small power to turn on a gate to send big power to the item.

I highly recommend using relays in wiring fog lights, multiple neons, and other high wattage lights. For LEDs, tap into the power wires you want. They pull so little current that you could literally wire hundreds on the same line before you get the same pull as one fog lamp. If you try to tap into a wire with something that uses too much current, you'll blow fuses, melt wires, etc.

Don't rely solely on the built-in amperage protection of a relay. Place a fuse or circuit breaker on the power source wire and the power feed wire of the accessory whenever possible.

Formulas

Ohm's law

Base

P=I*E

E=I*R

Voltage

E=P/I

E=I*R

E=sqrt(P*R)

Current

I=P/E

I=E/R

I=sqrt(P/R)

Power

P=I*E

P=E2/R

P=I2*R

Resistance

R=E2/P

R=E/I

R=P/I2

Where

P = Power in Watts

E = Electromotive Force in Volts

I = Electrical Current in Amps

R = Electrical Resistance in Ohms

sqrt = Square Root

Definitions & Materials

Circuit Breaker

Works like a fuse, except trips instead of blowing. It can be reset to work again, unlike fuses that have to be replaced once blown.

Cold Shrink Tape

A special tape that sticks and conforms to itself.

Core

The center (actual wire). Usually consists of copper but can come in a variety of materials.

Electrical Tape

Special rubbery tape that is used to seal electrical connections.

Fuse

A small plastic piece with a small wire inside. It blows the wire when it's rating is passed, preventing damage.

Gauge

The size of the wire; the smaller the number, the bigger the wire diameter.

Heat Shrink

A special rubbery material that shrinks when heat is applied; it is best used where water proof connections are needed

Insulation

The coating that surrounds the core. It protects and isolates current.

Relay

A device where a small amount of electricity is used to open a gate, triggering a larger power source to flow to the target object.

Tap

A small plastic connector that allows the connection of 2 wires without cutting and splicing.

Links

Electronics Tech v1.0

The previous version of the tech.

Ford CDs

Download the torrents for Ford vehicle diagrams.

Special Thanks

taylor0987

AZ2kVert

--Kuplex 13:19, 26 June 2007 (CDT)