HELP! On wiring diagram under the hood for a 72

[barracuda]

Anyone have a wiring diagram for a 72?
I just bought one ( my first vette!) and the guy who had it started to install a new wiring harness in the engine compartment but never hooked it up so now I gotta piece this puzzle together! Anyway it is a 350 with airconditioning if anyone has it could i possibly ask you to possibly fax me a copy of it I would think a lot o0f the other years would work also I am very anxious to get it running!!! Here is my fax# 361-775-1148
Thanks!!
David.

 

[eastnder]

Hi David,
I dont have a fax machine but Tom has this really cool site for 73's that has all the wiring diagrams for a 73. Good luck!
http://www.corvetteforum.net/c3/vette73/index.htm

 

[vigman]

Welcome to CAC

Congrats....

I have a 73 shop manual but Faxing will be a pain.

Ask the questions &I'll answer ( while I figgure out how to copy the info clearly)

Mike

 

[barracuda]

engine wiring on a 72

First question I guess is did a 72 have a ballast resistor (porcelain block ) and if so what wires go there? I have some wires on this new wiring harness that are cloce to the alternator area one connector has 2 wires connected to it a orange and black, then there are 3 different red wires that are all close enough to put onto the alternator along with a black one that is a ground wire I assume, but I am sure they all dont go there. Also what color wire hooks up to the posotive side of the coil there is a yellow one that might go there but I dont want to guess on this stuff. there are more wires that I need help on but ill leave it at these for now
Thanks!!
David.

 

[75SHARK]

The 1st thing I suggest you do is obtain a small clipping of each wire gauge (1 inch of) for reference. (10 -20 ga) And sandwich bet tape for labeling. This will give you a good eyeball ref for looking at wiring sizes.
No, your vette doesn't have a porcel block on firewall like old Mopars. Your Ign feed wire to coil (run position feed) is a 'resistance wire'. There will be a conn for coil + feed that has 2 wires 20 ga yel & 20 blk/pnk.
Your alt output is one 10 red. Two input alt wires are 16 B/W & 20 brn on one conn. A 12 blk grds alt case & heads fwd to join common grd w/hdlmp grds.
Now all this info is "factory" color coding. I would find out if harness you have = same, & who made it! If you don't know this, could be off by a mile & snap, crackle & pop!
I have your info, but no fax, scanner or dig photo. That's cyber life! Best of Luck -Dave

 

[vigman]

Factory Colors

Yes based on the previous post you must answer the following BURNING question.

Is it a GM factory harness or is it a painless or other aftermarket harness.. This is critical info.

IF YOU GUESS INCORRECTLY........ POOF

That being said..75 Shark is 100% correct, if these are NOT the wires you have.. stop and find out WHO provided the harness ( there should be an ID tape on the wiring or connector shell).

To be safe you should remove the connector and make a picture of the backside of the shell indicating what colors are what holes. That way we can ID the function coming from the firewall ( known GM wiring) and interface it to your new connector.

Mike

 

[barracuda]

will put up a pic of my dilema tomorrow

Ill put up a pic of my dilema tomorrow and if I cant post the pic can I send it to you all via e-mail?
Thanks again!
David.

 

[barracuda]

found out where some of the wires go! I think!

The 2 wires I was asking about that are close by the alternator area I believe they go to the horn relay according to the wiring diagram for a 73. One wire is black with a white stripe then it has a built in type diode or resistor in the wire then it comes out of that and is orange the other is red right next to it. Does this sound right?

 

[barracuda]

pictures

Here is a picture of the wires I need to hook up according to the 73 diagram some of them connect to the horn relay, but I can not find it anywhere unless it was removed with the old harness. Where should the location of the horn relay be at on my 72? Also I went to the auto parts store to just see if they had one to look at they carry th 67 to 71 relay and the 74 and up relay but not the 72-73 relay which is totaly different from the 71 or 74.
Anyone able to take a picture of the relay and the wires that connect to it?
Thanks!!
David.

 

[barracuda]

another pic of the wiring harness plug at the firewall

this piture is of the fire wall area where the harness hooks up most of the wires you see are are not actualy on top i had to take the picture kind of from the right side.

 

[Camtwister]

I will fax you a copy of the engine wiring diagram as well as the A/C wiring for a 71, should be close to the same.

 

[barracuda]

thanks for the fax!

hello thanks for thefax it has helped but I still dont know where the location of the horn relay is anyone know?
David.

 

[Camtwister]

The relay, on my 71, is on the left inner fender about the same distance from the firewall as the middle of the brake master cyl. (assuming you have power brakes).