Wiring

[shadowgray396]

I guess I will be the first to ask a question here. I have started on the interior of my 70 chevelle and plan to start the wiring on it. Any suggestions on what wiring harnesses to purchase(I plan to replace all the old wiring). or additional reference material other then the basic assembly manual would be appreciated. For example I'm not sure were all the ground straps go in the engine bay and behind the dash, so having something that makes it a little more clear would help. I'm starting from scratch and also a rookie at this.

Ray

[Hank70SS]

You mentioned the interior then engine bay, so it sounds like you're doing everything.

There are 2 main harnesses in the engine bay.

The engine harness has wiring for starter, ignition coil, wipers, blower motor, TCS, temp and oil senders. No grounds with this harness as the engine is the ground and it's connected right to the negative battery post. The wiper relay is grounded to the firewall by the mounting screw.

The light or forward harness has wiring for all forward lights, horns, voltage reg, alt, temp and brake warning lights. This harness has grounds that attach to core support on each side near headlights.

The chassis is grounded through the pigtail off the negative battery cable attached to the passenger side front fender.

There are of course additional harnesses for options like cruise control and AC.

As for grounds in the engine bay what I mentioned is about it. Now if the car came with a radio then you'll have 2 braided straps off the valve covers to the firewall and one down lower on the passenger side of the engine. If it was an FM radio then I believe there was a 4th ground strap. These are not circuit grounds, they are not meant to carry current, only meant to help suppress ignition electrical noise. I would not add these until the car is finished and running properly. Then you know all the circuit grounds are good and the radio ground straps are not acting as circuit grounds.

Then there's the dash harness, the other main harness in the car. It's pretty obvious what it does, it has the fuse panel that connects to the bulkhead connector on the firewall, engine and light harnesses.

The headlight switch has a metal ring around it that is part of the ground circuit. It has a wire that attaches to the metal bracket for the wiper switch. The wiper switch bracket get's bolted to the metal dash frame. There should be 3 (?) ground wires in the dash harness, one goes to parking brake assembly. One to the metal bracket that goes to wiper switch, connects where the bracket is bolted to the metal dash frame. One to the back of the gauge cluster. The circuit board is grounded by the wire just mentioned and 5 screws that hold it to the gauge cluster.

Again there are additional harnesses, like console extension, rear light harness, actually 2 harnesses on a 70, and others. If you're replacing all harnesses you're talking major bucks. The dash harness is the most expensive and runs close to $500.

EDIT: I'm sure we can find some pic's to help out. If not my dash is coming out soon so I can restore it, I can take some pics then.

[shadowgray396]

Thanks Hank, for the info. any pictures always help. When I got the car it was already torn apart otherwise I would taken them.
Ray

[Hank70SS]

Where are you in the process? I won't be starting my dash for awhile. If you need dash area pics sooner we can find some.

[shadowgray396]

Probably won't start the dash until next month. Need to get the parts in and plan to drop the head liner in first and get the insulation on the fire wall done.
Ray

[rak1]

Rewiring a car is fairly easy as long as you understand how to run circuits, crimp, solder, and can read a wiring schematic. But before you start be honest with yourself and ask yourself a question "Can I rewire a car on my own, or I'm I more of a plug and play type of person". If you are a do it yourself type then I would go with a Painless wiring kit and save allot of money; complete kits cost about $400, but it takes time to do. Think of it as it save money but it will cost me time; what is your time worth? To completely wire a car using a Painless kit takes about 30+ hours to do from layout to testing. Now if you're more of a plug and play type of person then go with a kit from M&H or one of the wiring companies that make complete assembled kits. All you have to do is remove one harness and plug in the new one. These kits show you everything in pictures and it's very easy to do but it works the other way meaning it saves you allot of time, but costs allot of money and don't be surprised if the cost exceeds $1200 if you have to replace everything. Some harnesses alone cost over $400 and that's just for one harness and most cars have four. As you can tell I went with the Painless kit because I didn't want to spend allot of money on a plug and play kits and I wanted an upgraded fuse block with new style fuses. Also I've done allot of wiring so it was kind of fun for me and I know I did it myself so if I need to add a circuit I can. Just remember to do one circuit at a time and don't rush is thekey. Either way getting new wiring gives me peace of mind knowing I'm not running forty year old wiring which is a big plus for me.

[Hank70SS]

The problem with the Painless kit is it's not made specifically for one car. So you do have to know how to crimp and solder. You can buy harnesses made specifically for your year Chevelle. Then it's matter of of plugging the connectors into the correct spots. They make harnesses that have the correct connectors and color coded wires for every year Chevelle, a reproduction of the original harness. Painless harnesses are a lot less expensive but they're more generic. Just depends on your abilities and what you want.

[rak1]

Not really true anymore they are making kits for early Mustangs and Mopar "B" bodies and I think they are just starting to do kits for some Chevy's too. I helped a friend install a kit into a '66 Mustang and it was a snap; it even had all the ends terminated, etc.

The problem with the Painless kit is it's not made specifically for one car. So you do have to know how to crimp and solder. You can buy harnesses made specifically for your year Chevelle. Then it's matter of of plugging the connectors into the correct spots. They make harnesses that have the correct connectors and color coded wires for every year Chevelle, a reproduction of the original harness. Painless harnesses are a lot less expensive but they're more generic. Just depends on your abilities and what you want.

[Hank70SS]

If they have kits for the Chevelle then that would be a good option. I've only seen their 'generic' harnesses. They're good when doing a custom car/wiring.

[shadowgray396]

I did notice an add on TC where you can get the original checked and rewired if needed for about $200, and all the wires are marked where they go. He only does the harness with the fuse box on it.

[Herbie67SS454]

I guess I had more time than money so I redid my harnesses myself.
I did one harness at a time. Then one wire at a time.
I unsnapped the bulkhead connector for the forward wiring harness and then checked, cleaned, and redid each individual wire if needed. Hooked it all back up.
Unsnapped the bulkhead connector for the engine harness and did the same thing.
With both connectors loose, I took the fuseblock and dash harness loose and cleaned, cleaned, and cleaned, the fuseblock and cleaned, checked, and redid what wires were needed.
Then moved on to the harnesses back to the rear end of the car.
Took a while but I am happy. I had lots of new wire, soldering gun, and heat shrink, and connectors.
I also used up a few roles of the cold shrink tape.
When I got into it, I was amazed at how many wires had been spliced over the years and just twisted together with electrical tape over them. :eek:
Real pain to rewrap the wires with the cold shrink tape. Looks good though.
I did have a friend helping me. He has a lot of knowledge of electrical systems and we installed some inline fuse links.
Everything works except the horn and all those parts in the steering wheel, horn relay, and horns are new. I'll get it figured out. I can ground it out and the horn works. Something in the wheel I think. Not bad for a car that sat here at the house with the engine/tranny out of it for 17 years.
If I had the money, I would have went with the plug and play harnesses but close to $1500 bucks.
Best of luck.

[Notalent]

Im about to go through this, but since im not a numbers matching kind of guy on this Chevelle I decided to go with the American Autowire Kit. Pretty much a plug and play deal with additional circuits for extra options. Its about $500 for the WHOLE car, not bad in my book. All the connections are made to original spec so there should really be not much cutting/soldering except on aftermarket goodies like stereo systems, alarms etc...I plan to start this project in the next month. Here is the kit I am getting:

http://shop.americanautowire.com/classicupdatekit-1970-72chevelle.aspx

[rak1]

Nice; it looks allot like a Painless kit with the new style fuse block, wiring, etc but it's looks like the connections have already been cut and terminated like the kit they make for the Mustangs. Let us know how it turns out! On my Camino I covered the bulkhead whole using two steel plates and gaskets using the factory holes and just adding bolts that go thru the same locations the factory connector used. I then mounted the new fuse block to the plate so the fuse block is in the same location as the old one. Also It was nice because I didn't have to cut any new holes since the block is in the same location I just used the factory holes.
Im about to go through this, but since im not a numbers matching kind of guy on this Chevelle I decided to go with the American Autowire Kit. Pretty much a plug and play deal with additional circuits for extra options. Its about $500 for the WHOLE car, not bad in my book. All the connections are made to original spec so there should really be not much cutting/soldering except on aftermarket goodies like stereo systems, alarms etc...I plan to start this project in the next month. Here is the kit I am getting:

http://shop.americanautowire.com/classicupdatekit-1970-72chevelle.aspx

[Hank70SS]

That's a nice looking kit and good price. Let us know what you think once you start installing it.

[jnorton]

Hey, Herbie. I'm kind of in the same boat as you. I have more time than money. I'm also interested in keeping things original as I can along the way. I do have a couple questions for you based on your experience. What did you use to clean the harnesses? My car was undercoated, so the bulkhead connector is pretty caked up with that stuff. Also, where did you get your cold shrink tape? I've never dealt with it before.

[Chevelle_Nut]

Now this is the way to go, yes please keep us posted.

[shadowgray396]

I agree keep us posted, great price.
Ray

[Herbie67SS454]

John,
The cold shrink tape is a non sticky tape that looks like the factory harness tape. I bought mine at a local auto parts store. You stretch it around and it sticks itself.
Good trick at the end of a wrap: Take some fishing line and make a loop. Put the line on the tape where you have already wrapped when you only have 2-3 wraps left. Keep the loop end hanging over where you will end. The tag ends are hanging out the other side. Wrap the last few wraps over the line and cut the tape with a little extra. Stick the end of the tape thru the loop. Pull the tag ends until the line snugs the tag piece of tape. Now jerk the tag end of the fishing line. This will pull the end of the tape under the wrapped tape. Never have to worry about coming loose. Learned this wrapping eyes on fishing poles.
You can use some laquer thinner and a brush to clean the outside of the connectors.
Electrical contact cleaner and a small wire brush also to clean the insides.
I unwrapped all the old harness. One harness at a time. I then replaced any wire that was cut, spliced, or brittle with new wire of the same size and length by soldering the new wire to the old and heat shrink over the splice. Butt connectors and heat shrink would work also. Really have to take your time if you do it yourself.
I wrapped all the wires with the cold shrink tape. I had a friend help with part of it and he would hold the end I started with and I would pull the wire tight while wrapping.
I also got some started and then tied to a post to do by myself.
A wiring diagram for your car is a must. Never could have done it without one.
Hope this helps.
We painted my car here at the house, I installed all trim, and I installed the interior myself.
If you have the money, the plug and play harness will save a huge amount of time....
so will a "good" body shop and interior specialist.
PM me if I can help anymore.

[Ray Barnes]

Just finished my dash harness like you described. I took it one step further and disassembled each wire from the connectors and used a small wire wheel on my Dremel to clean each brass connector. I then took each copper light contact (little rivet type) for each light bulb socket and put in a solution (vinegar and salt) to take any corrosion off. I used lacquer thinner to clean the surface of the wires.

If you want to get the brass tabs out of the plastic retainer clips, just slide a small screw driver inside the clip a pull lightly to remove. You shouldn't have to pull hard if you depress the tab that holds it in the plastic clip. You will have to bend up on the brass retaining flange before you re-insert it or it wont stay in the plastic clip.

[Notalent]

Will keep you all updated. I will take some pictures as I go. Just got to wait till next payday to get it ordered and finish up the suspension and firewall. Than I will place the engine back in the frame rails and get to work!

[jacen33606]

I just purchased the same kit for my 72 and will post pictures as well.

Jacen

[rak1]

Any updates?

[Notalent]

Nope. Just got the engine, trans installed. Waiting for my tax money and I will order it up. Im ready for the wiring. May just bite the bullet and use a CC until I get my $.

[Notalent]

Got my AAW kit in yesterday. This kit is awesome. Every wire is marked, OE connections/terminals, updated fuse block, great instructions. I plan to start to tackle this in a week or so.

[macsmobile]

Hey guys if you all need any distributors, coils, or wires check with me on prices. Find your price for something and pm me and i will see if i can beat it.