Gordonm

I need to get a good diagram for a 77 AC harness. Replacing the front engine and AC harness and have about 90% of the wiring figured out. It is an early 77 also. I have a 79 diagram but some of the coloring is different and it is also slightly different.

0Willcox Corvette

Gorman,

I know I have a better one, but upload this off the site and I'll look for the GM one for you. I'm sure I have it on this computer. http://willcoxcorvette.com/repairand...lp.php?hID=289

Post when you have it uploaded... I don't want to leave this one up on the site.

Ganey

This may do it for you, wiring from 1977 Electrical Troubleshooting Manual.
http://www.europeancorvette.com/phot...77/Page016.jpg

I have the 77 factory A/C wiring diagram, however would need to scan it in.

...Roger...

Gordonm

I already have this one, the only thing it does not have is the AC diagram. That is the one I need.

Gordonm

Roger, that is the best one yet. Any chance you have a clearer one that you could email me?

...Roger...

That one is from this site , it might be clearer if you go to the site.
I have a 77 manual but I can't get my scanner to work with my laptop. If the one on the site is not clearer when my girlfriend gets home I'll see if she can scan it for you.
http://www.europeancorvette.com/html...l_diagrams.htm

Gordonm

That is fine. I just saved that in my favorites and will refer to it when needed. Thanks for the info.

...Roger...

Sorry Gordon I tried but I can't get the &*$@#% thing to scan.

Gordonm

I know the feeling.

76yellow

Try searching Index of /johdotukset It's a treasure chest of corvette wiring diagrams.

Artsvette73

Here is one

Gordonm

Artsvette73, thanks. That is what I was looking for. I think I have the wrong relay. One of the connectors on the relay should be a two prong and there is only 1 prong on it. This explains it.

...Roger...

Some of the passenger car relays ground through their mounting rather than using the black wire as the Corvette does. I would put the correct relay on but you can try grounding the case of the relay you have on the car now.

Gordonm

What I have is the two connectors that go to the relay have a 3 prong and a 2 prong connector. The relay just has a 3 post and a single post. I do have the black ground wire connected to the harness. I think maybe the relay is just the wrong one. It should have 5 prongs on it instead of 4.

...Roger...

Yes it is wrong but if its the one I usually run into its just the black ground wire. A jumper from the black ground wire to the case of the relay will probably make it work. On the vette relay the jumper to the case is internal. 10 bucks will get you the correct relay.

Gordonm

OK ut how is the relay grounded. If the black ground wire is not connected to the relay in any way you are saying I need to run a wire from the case to the black wire? why not just get a relay with the proper terminal and ground it correctly. It looks like there are 2 different relays for the 77, an early and late. This car is an early and hopefully the harness is for an early car also. I did not order the harness or the relay. Minor problem but these are the things that bug me.

I'll have to take a pic and show it. It does not even look like the connector goes on that way.

noonie

The correct early 77 relay

Gordonm

Thank you. That is what I figured but wanted confirmation.

noonie

I don't know if you're into some minor mods but this is what I did.

The large lug ground wire mounted to an accessory hole at the back of the head, easy to get to and prevents future mishaps, No need to cut any wire either. Just be sure to use a short bolt.



Use a ga wire to match the power wire to the blower, splice and solder it to the original ground wire right at the blower connection and I ran it straight down to the frame below, drilled and tapped and used copper antisieze.
I could tell a increase in blower rpm just from this.