I just bought a 78 vette and there is no power to any of the options. There is a hard line running from the distributor the the battery just for starting the car. After going through some of the wiring and finding snipped wire after snipped wire I have landed on the option of installing a new harness. I would appreciate any tips, part recomendations, or even alternate options from anyone!

Thanks

p.s. I just joined a site minutes ago, hope this pays off with my resto!

 

Welcome, the harness splits into 3 main componets,
1. main harness inside the cabin.
2. Engine harness outside under the hood.
3 .Outside front lights.

you will need to define what your doing repair ? Restoration ? Frame off?
replacing the outside harness's is fairly easy, replacing the main inside harness,
is not a rookie job. major Dissasemble.

If your doing a full restoration no problem your ripping everything out anyway.
If your repairing trying to get to work, I would focus on repairing what you have first.

sounds like you bought Bubba's car, get a good set of schematics for your car.
If your not a Electronic tech. your in for a rough ride.

There is no better site for corvette info than right here. 69VETT

 

Well the interior is a little rough anyway, looks like someone may have tried to figure out the problem before and fell short. So most of the dash and center consol are "loose" for lack of a better word. Im prob gonna need to replace all 3 levels anyway. I've never seen such crack pot work in my life but I got the car for a steal so im not complaining. Anyway, would you happen to know a place that I could find the schematics? A good place to buy the harness with good customer support? Also, thanks for the welcome, who better to ask questions than the people who have been there before.

 

So does the car run? If so, do you have to reach under the hood and plug stuff in or anything crazy like that?

Depending on your comfort level with electrical things, you may just want to replace the full front harness, which contains the engine stuff (Charging, ignition and sensors) as well as the lighting (Headlights, turn signals and such)

I'm not completely sure about the '78, but the main bulhead connector for the harness should be under the brake power booster and has a single bolt holding it to the fire wall. If you've got a good schematic, you can pull all this out and re-splice and clean up the existing harness.

There are a few companies out there that have replacement harnesses, and some that even have all the proper connectors to make it as easy as possible... they're just pricey.

Shawn

 

Here's a very good set of wiring diagrams for a 78'

Gary

http://www.corvetteforum.net/c3/tune...l/index6.shtml

Buy the harness at Letric Limited, they are direct replacements. Use tape to label the connectors you take them off.

http://www.lectriclimited.com/

 

yes the car does run, I have to connect a wire to the bat that comes from the distributor, turn the key, and at the same time push a button that was installed by one of the previous owners to start. that was my origional plan to just fix what needed fixed but the wires are everywhere, nothing goes to anything so I have no clue where it is supposed to go.

 

Anyone know anything about the company "Painless"? Thats what I was recomended by one of my buddies.

 

I don't think they are plug and play. You may have to cut the connector off your old one and splice it on to the Painless harness. Maybe someone that bought one can chime in.

Gary

 

I would suggest wiring diagram from Docs rebuild.

 

78AE,

We have the factory harness's on sale in the forum special side. I have them from 1968-1977 done, but I'm working on the 78 right now. I'll post you a link when I'm finished. I don't think you'll find new factory harness's cheaper anywhere.

Willcox

 

Here is the link for the 78 harness's.

http://willcoxcorvette.com/advanced_...ywords=HARNESS

 

You must get a copy of the Chevrolet Assembly Instruction Manual (A.I.M.) for your 1978 Corvette. It shows the location and proper routing for all wiring plus it has the wiring schematic included. Search the internet for sources of factory-exact wiring harnesses for vintage cars. Research them well and select what meets your needs best. Most are very close to original; but some are identified much better than others. If you need that feature, choose appropriately.

You can generally salvage the 'unique' connectors that still exist on your present harnesses. Usually, there is a retaining tab on the side of the pin at the end of each wire which holds the connector in place once the pin is inserted. If you insert a small jeweler's screwdriver tip into the end of the connector, it will compress that retaining clip and you can just pull the wire and pin out [without any resistance].

Identify the lines coming from all electrical devices in the car and find them on the electrical schematic. Code them with the color of wire and type of connector that should hook up to it. That will make it easier to properly connect the harness when you are ready. It will also make any 'unattached' wires stand out so that you can determine where they go.

Good luck with your project.

 

7t1:

Unfortunately GM stopped putting the schematics in the AIM’s in 1971. Sucks! But the books went further in showing you where each connection plugged in to. The 1978 book will show you each and every connection (some pics are faint in this book).

On the PDF version we did we tried to clean up some of the pictures, but at least you have the zoom ability which makes things easier to see. This book is listed at a discounted price to forum members here. http://willcoxcorvette.com/product_i...ducts_id=25582

I wish the 72 and newer books had the schematics simply due to errors I’ve found in the aftermarket repair manual schematics. (Even the 69-71 GM aim schematic has an error on the wiper relay and the 68 AIM schematic is a mess).

The best schematic seems to be the one from Dr. Rebuild, Lectric Limited or Don Olsons colored laminated schematics. The Docs schematic is wicked on the ones that I’ve seen. I have one here for every C1-C3 I own. At first I found them a bit busy and hard to follow, but once I got used to them I was more than OK with it. Showing the connectors as a picture and the wire colors comes in pretty handy.

For simplicity and cost sake for someone used to reading old style schematics I’d go with this one. http://willcoxcorvette.com/product_i...ducts_id=26664. It’s only 11.00 and what I find nice about it is you can trace circuits with dry markers and when done you can simply wipe them clean.

Willcox Inc.

 

Good advice...

 

I did my '72 dash, rear, and engine a few years ago....some things that will help you...

1) patience, patience, patience....it is going to take time and move slowly.

2) either Wilcox or lectric limited make a great harness and stay with either one

3) get a colored schematic from Doc's. I can not say enough that his laminated sheet used for about $20 is worth evry penny. Using it with an assembly manual made it a breeze (a slow gentle breeze....read No 1)

after I got my dash harness I laid it out in a warm place (it comes coiled so this help when stretching it out in the floor boards. I worked from the fuse box end to the far end. As I attached each section of the new harness, I taped the old section back onto its trunk to keep it out of the way....eventually each old section ended up wraped around itself. By the time you get to the end you will have less wire to manipulate. Plan on changing any bulbs, relays, etc while you have the dash apart. You will hate to have to open it up again later. Because of age and the way plastics were made back then, expect some parts to be brittle.

best of luck...rt.

 

I would like to thank everyone that has pitched in advice. I'm a little more confident in my choice now. I WILL be purchasing my harness from either Willcox or Lectric, just need to do a little more research but they seem to have what I am looking for. Also I'll be purchasing the laminated color schematics from Doc's and a GM assembly manual. I appreciate all the help and I promise to offer up any advise that I may have in the futur.

Thanks a bunch,

Jeramey

 

Corvette,

No problem and if you need help just email or post again. BTW, hour harness's are made by Lectric Limited.

Willcox