Time for wiring tips and tricks, got any?

Most points have already been covered, but here's some tips I followed when wiring my 49 Chev in a similar fashion to what you're doing (basic lights and engine wiring, plus fan and fuel pump...no blinkers or reverse lights)...

1. WIRE ONE COMPONENT AT A TIME! For my car, I used the fusebox (aftermarket job that holds the blade type fuses) as the central point in wiring each component. One end of a given fuse goes to the component, while the other end handles current input, either directly or from a switch.

By wiring up one component at a time and building your harness on the car as you go, you avoid confusion...and it makes testing each newly wired component a breeze!

2. WIRE IT LIKE IT'S A FIBERGL*** CAR! By that, I mean run ground wires to EVERY light and component. As already mentioned, don't rely on the body or the component for a good ground. Many electrical glitches are caused by bad grounds...avoid that problem by running dedicated ground wires to everything!

3. WHERE TO GROUND STUFF? My trick for wiring a car is to hook the negative battery cable to the engine block, then run a heavy Ford type switch-to-starter battery cable (eyelet on both ends) from the block to a bulkhead on the body...usually on the firewall. The ground wires from individual components also terminate at the same bulkhead, providing a solid, reliable ground. This is admittedly overkill, but a hefty 4ga ground strap means no grounding issues down the road!

Under the hood, I will run a ground wire from things like the headlights and electric fan back to the negative battery cable from a smaller bulkhead...no need to run the grounds for these things back inside the car if the battery is right there!

4. HEADLIGHT RELAYS! Yes, as people have already stated, using relays for your headlights is an excellent idea! I don't use one relay for each lamp, though...I use one relay for low beam and one relay for high beam, so that if one relay fails, you still have a back-up plan that gives you TWO working headlights.

5. COMPONENT/SWITCH LOCATION! Take a few minutes to think about how and where you are mounting things. For example, I put my dimmer switch up on the dash to keep it out of water and dirt on the rusty old floor. Keeping your electrical components and switches clean and dry is essential for obvious reasons...just think about it when you decide where things will go!

6. GREASING CONNECTIONS! I use a compound called No-Ox-Id that looks and feels sorta like ch***is grease, but it provides a weather resistant seal and helps keep current flowing freely. I add it to each connection to eliminate any worry about corrosion on down the road! Other brands and variations are available. Don't be cheap...buy some and use it!

7. KEEPING WIRES OUTTA TROUBLE! Here's where I REALLY go overboard! I use rubber hose in various sizes to protect all my wires where they come into contact with anything metal. Never rely soley on the wire's insulation to protect the conductive part inside from becoming exposed due to rubbing and vibration...always use grommets, shrink wrap, electrical tape and even hose lengths to insure that your wiring harness outlives the car it's on! ANYWHERE a wire rest on or p***es through metal (like the firewall), it NEEDS to have an extra measure of insulation around it.

Those are just some basic 'rules' I follow when wiring a car...some may seem overkill or too extreme, but I like the peace of mind that comes along with knowing that my electrical components are safely wired and will work as designed for a long time! A little extra time, thought and money spent on your wiring will save you countless headaches and h***les later!

 

Does anyone have a source for GM color codes?

 

DON'T use cheap crimpers!! Klein Tools makes a decent set.

 

Where did you get your fuse panel?

 

That is a panel that I sell from PARR Automotive.

 

I've wired several cars with Painless kits... and I usually have to cut the wire ties off them so I do not have a lot of wires doubling back.

Map out all your lights, switches and stuff on your living room floor. Then lay the box there and run the wires where they need to go. Use electrical tape to temporarily tape the wads of wires together.... because as wires go around corners and make bends... the wires on the inside of the bends will be shorter, outside ones longer... so you'll have to re-tape or wire tie.

Mount box.

Then run looms where they need to go.... think of the routes your wires take as city streets... and don't cut across old man Harpor's yard to run a wire to the headlight switch...

When you terminate ends... take your basic plastic insulated connectors, and pull the plastic connectors off... I found some that come already plain in my dad's electrical pile... he was an electrician... anyway, you can make your own.

Then cut several pieces of shrink tube for your wires... do them all at the same time, so they all end up the same length. Avoid the cheap Radio-Shack shrink tube... buy your stuff at an electrical supply store. (you knew that already, 'cause you're a sharp cookie). I take and draw two parralell lines on my wood topped work bench with a ball point pen... and then use a razor blade to cut them all the same length...

Then slide the shrink tube onto the wire... cut your insulation back on the wire, slip the connector on... crimp it (try to find the ones that can crimp on the wire and the insulation) and then heat the heat shrink on...

I'll try to post some pics of this later tonight if I have time...

Sam.

 

I AGREE WITH 32LIMEY CRIMP AND SOLDER,USE SHRINK TUBE.

 

All great idea's.


..........Mount that Halon extinguisher then wire car....H

 

Think about how Detroit does it. They make a master body harness, then a harness for each major components (motor, front end (lights, etc.), out back). I've seen more rods that were hard to work on because there was just ONE BIG harness. Now way to remove or unplug if needs be. Also, you can get a 21 connector weather pack bulkhead plug and socket. Keeps the weather out around where the harness must p*** from interior to exterior

 

Like Bruce, I always used STAR WASHERS (they have teeth on them to "dig" into the connection) on every mechanical wire joint I made, until this piece "p***ed over" my desk.

Heck! I always used star washers on grounds!

This is part of a recent GM service bulletin......

This information applies to 1996-2005 p***enger cars, trucks and utilities.
(but would apply to any newly rewired vehicle)

In the past, star washers have been used under most ground connections.
It was believed using a star washer would improve continuity to ground and prevent the ground fastener from becoming loose.

GM Engineering has determined that installing a star washer increases the chance for corrosion and prevents the terminal from achieving proper torque.

On vehicles being built today, star washers are NOT being used under any ground connections.

It is recommend NOT to use a star washer on any ground connection to the body or ch***is of the vehicle.

TIP: Be sure the fastener and terminal are clean and corrosion free. When removing corrosion, be careful not to remove the plating from the terminal. Use dielectric grease between the connection and the ground point.

Also be sure to torque the fastener to the proper specification.

I guess you CAN teach an "old dog, new tricks!" (anyone need a supply of un-needed star washers?? )

 

I'm in the process of wiring my '32 coupe ch***is. Two additional questions: does anyone know a good sourse for info on fuse sizes for each individual circuit like headlights, heater, horn, etc? Also, I've not heard of a relay for lights, what's that all about. I'm setting up my ch***is like Henry did with all my electrical running to the dash tunnel so I'll be able to start the ch***is before I mount the body. Any good advise for this application is also welcome. Thanks dug

 

No one knows the GM color codes? I'm trying to build my harness from scratch.

 

headlamp relay modification - http://www.danielsternlighting.com/tech/tech.html

I spent about $30 in wiring, connectors and relays doing mine. Not difficult at all to do or understand.
d

 

as for soldering; years ago i bought a "pencil tip" soldering gun that uses a bic lighter and puts out a small sharp pointed flame. has anyone used one to wire a car with? that's what i bought it for but have lost it since then without ever wiring a car (i hate electric soldering guns). but i'll get another one if the consensus is that they work good. i need to do some rewiring on clarence. (right, jim c?)

sam - i like what you're saying; have you ever soldered in addition to crimping? opinion?

 

First, I envy all of you that can wire a car from scratch. I am a kit person, as electrical scares me..(hated electrical engineering cl***) as I can not see it, only feel it.

Can someone better explain the headlight relay, where you put the relay, how it is wired in.. I lack this knowledge but would like to know more to get better educated, so maybe one day I feel confident enough to tackle a job from scratch..

 

atch, the Bic "Torch" will work for smaller connections.

I usually "tin" (flow a small amount of solder) on the ends of the wires after I have twisted them tightly.

Slide on the shrink tube.

Then crimp ** the wire in a terminal end. (non - insulated type)

Then I put heat on the terminal end just where the wire "peeks" out the inside of the terminal; and apply a small amount of solder, (ROSIN CORE ONLY!) until it "wicks" into the terminal end. Don't apply TOO much solder, or it will continue wicking past the terminal end and on into the wire itself. This will insure a good mechanical and electrical joint.

Once the connection has cooled, slide the shrink up UNTIL IT COVERS THE END OF THE WIRE THAT PEEKS OUT OF THE TERMINAL (inner end) I actually push extra up against the terminal. It will pull back when the shrink tube shrinks. This way the solder joint will be totally covered as well as the outer end of the terminal.

Then using a heat gun (or a hair drier) contine applying heat (rotate the wire to get an even shrink) until the shrink tube is tight all the way around.

** Even if your only going to wire ONE car; invest in a GOOD SET OF CRIMPERS!

AMP, KLIEN or any kind that have FORGED crimp indentations. Leave the stamped cheapies on the $1.00 table; waste of money.

 

Ive done 5 cars then I decided to get a kit... No biggie I just soldered all the connections and heat shrinked em. I also use spade connectors on anything that may be removed later and use good scotch (3m) electrical tape to cover em from the elements. I used to make my own fuse panels with the gl*** fuses and everything and never had any trouble cept the time i hurried on my 30 sedan and forgot a grommet and the new buyer drove up to the micro brewery about a 1/2 mile and a wire rubbed thru and fried the alt wire **** I had my money.. Actually it was no big deal and the car drove to the east coast.
Dave
Oh ya get a after market headlight switch with a breaker .....fuse everything good...............I even had a ford alt and regulator on a sb chevy once and they asked me how i did it...Used a motors manual

 

These guys http://www.riwire.com/ have every color combination imaginable.

I buy all of my lacquered cotton covered wire from them.

 

The ground terminals on new cars have a ribbed pattern on both sides.

FWIW, I'm still seeing ribbed terminals and star washers on the relatively new cars I'm dis***embling in the shop on a daily basis. Winter weather is great for my current line of business -- collision repair.

 

Joining two pieces of wire together with solder is always a challenge. I have tried different approaches but here is the way I do it now. I cut about a 4 inch piece of s**** wire and strip back the insulation all but about the last inch or so. That keeps the strands together. I pull out of this bundle one strand of wire. I use this single strand to wrap the area of the two wires together than I intend to solder. This holds the two wires together while I solder. Seems like any other method I tried, the wires would separate or move just as I was ready to solder.

 

i dont know the codes,but maybe this could help you somehow?

http://www.tocmp.com/manuals/wiring/index.html (old car manual project,car wiring diagrams)

 

in my electrical cl***es at MMI,they always taught us,that when we splice connections or put on spade connects,or anything that needs crimping to solder them,and then crimp,then heatshrink.


also to join to wires together,we always cut about an inch of insulation off each wire,then we braided the wires around each other,so you couldnt pull them apart,and then soldered them,works great and it hard to pull apart even without solder

 

Well, it is a surprise to see an old forgotten post resurface. After this post, I finished up my wiring on the Touring.

One of the things I did was to solder all my connections, even the terminals.
I have always liked shrink tube, so I used a bunch of that.

I used a bunch of self adhesive wire holders, the kind you run a zip tie through to hold a wire or wires.

All in all, it came out pretty good.

 

Well I do not know what to think about the star washer deal. I would say that I would still use them. I am kind of set in my ways. I mean they have worked for all these years, why change now. My only thoughts on not using them would be where you have a computer controlled or electronic device that is voltage sensitive. Maybe that little bit of corrosion would make a difference. Just when you think you are doing everything right , someone changes the rules.

 

here's a few more tips that I've used:

I used two small fuse panels from napa. They each hold 6 blade type fuses. I have one wired to constant power and the other wired to power with the key on for accessories.

For the headlights, I used a circuit breaker with blade terminals on the back that plugs into the fuse panel in place of a fuse. I used a 25 amp breaker. I used a universal napa headlight switch (with no dash dimmer or ****) that holds a 30 amp fuse, just in case the breaker dosn't catch something.

I have a pull switch for an electric fuel pump, in addition to my stock one.

Horns, use a relay.

I like to run wires for the same things together, like all the turn signal wires, bundled together with zip ties every 6 inches or so. After you have several bundles like this running near each other, tie them together every foot or so. Preferably a different color so you can easily tell which ties to snip to access on circuit. It makes it neat and easy to troubleshoot if needed.

I used a fancy label maker that was a gift to make neat little labels for all the wires, plus color codes that I made up as I went along and wrote down. I also used it to label each fuse on the panels, and label when each panel was hot.

All the wires under the car I used plastic loom to protect.

Disconnects are a good thing to put where needed. I like to have them on the lights outside the car, so if a parking or taillight ***embly has to come out, you can disconnect it.

I also like to use shrink tubing on all connectors.

Be sure to leave plenty of slack, makes troubleshooting that much easier.

I liked the book "how to wire your streetrod" for lots of helpful info if your not buying a kit.

I did my '47 like this. I don't have too many accessories, but I did put in a hidden radio with 3 speakers, courtesy lights under the dash, a trunk light that comes on with the lid, and all the basic stuff, plus lighting for gauges under the dash. Nothing much, but I have more than enough circuits.

 

Everyone seems to bash on the idea of using the body and/or frame as a common ground. The usual problem is that connections are made through painted or otherwise insulated surfaces. Here's a trick that gets around that. Weld 1/4 or 3/8 bolts to your ch***is, firewall, the back of your dashboard, etc and use them for a solid ground connection. If you're planning to use the ch***is/body as a common ground, run a heavy wire between the block and your ch***is/body. It also helps to run a wire between the body and the ch***is.


Ed

PS- Check out www.madelectical.com for more ideas.

 

Always use a fusible main link (55-60Amps). from the battery to the main circuit. 10ga or higher for main wires through the firewall. 4ga or higher for the starter (shouldn't exceed about 2-3 feet in length.. the longer the length, the higher the gauge you'll need to deal with internal resistance at starting time).
If you're using an electrical cutoff switch (kills all power) put it between the negative terminal of the battery and the frame and use the highest possible guage wire and the shortest possible run to connect it (the generator/alternator does not necessarily need to be isolated since it cannot generate the power of your battery at low rpm and has a much higer internal resistance).
Intrumentation wires should be 16ga or higher depending on loading and all connections should be soldered and coated with heatshrink to minimize short circuits.
Make a schematic and label all wiring colors. if you don't understand how a certain switch works either use a meter to figure it out, or consult a haynes or owners manual.
Electrical components outside the cab should be mounted to the firewall or driver's side wing and waterproofed.
You can choose any fuse box you like, but consult your schematic to guarantee that it has enough circuits to service the car. ALL power ciruits must be terminated at the fuse box or else you may have a fire if one fails.
All wires runs should be covered when p***ing through sheet metal or any abrasion area. flexible wire loom makes wires easy to service later on and usually looks discrete. if you're looking for fabric coating, you'll have to make sure that it is fire resistant.
It's good practice to use factory connectors where possible even if you do not use all of the functionality. If you need a new steering column you or the person who bought your car won't need to spend lots of hours figuring out custom wiring for a common part.
Where possible, keep all wiring to the front and rear sectors of the car as high up from the road as possible and if it absolutely must be exposed to the road, mount it on the side of a rail using any permanent fastener. generally avoid using zip ties, with enough vibration and weather exposure, they'll cut right through wires or come apart and drop the harness. the best way to secure wires it to use either the factory mounting flaps (little metal tabs that are welded to the fram and flex over the wires) or screw down, rubber insulated mounting brackets.
You may want to just buy a new harness, because making them is a pain in the ***. especially finiding the colors and connectorizing them.. you may have to modify a replacement harness, but a few modifications beats tracking down a used steering column connector or a firewall connector.

-Richard

 

The function of a relay is to control a high current line using a low current control. In simple terms this means that you don't want to run all the current through the switch that turns your lights on and off...the switch would be HUGE. When using a relay the only current required at the switch is that which is needed to actuate a small electromechanical reed switch inside the relay. In other words, the current through the switch is very small...the high current going to the lights now runs through the contacts inside the relay.
The best example of a relay is the solenoid on your starter...could you imagine the size of your ignition switch if all the current that turned your starter ran throuch the switch instead of the solenoid?

 

First of all I am not a big fan of complex color codes, GM or otherwise. If you have a cable running to a component in your car what are the chances that there are going to be more than a handful of seperate wires in that bundle? Red is always hot and Black is always ground...the rest is up to you. You are not building a hotrod for production that has to be serviced across the globe, do what's reasonable for you and then DO***ENT it in detail.
I have seen some of the prefabricated wiring harnesses and, while they are good for the average car, I am not impressed by the quality of the wire...I should say, by the quality of the insulation on the wire.
If you can find teflon insulated wire then use it. It won't chafe and it won't melt...either through the process of soldering or by external heat from engines etc. I have a 94 Jeep that I bought new and now have over 161 K miles on...the valve covers have never been off of it but I have had three failures in the wiring under the hood related to insulation becoming brittle and causing the wire to fail.