The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)

- Electrical (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=64)

- - New wiring (https://67-72chevytrucks.com/vboard/showthread.php?t=813088)

I want to say this is not mine and I take no credit for it. This is copied off the mad electric site. I thought it would be nice to have it so it's easy to find.
Here is the link. It's worth it's weight in gold to read and book mark for later problems.

http://www.madelectrical.com/electri...evymain1.shtml

If you are fixing to do a new wiring job please take a look at this. It should really help you and the vehicle out if it's built before 1973. The vehicle will operate even better if your doing a upgraded alternator. Make note the splice is the fire wall mounted distribution block now.
The other schematic is the factory one.:chevy:

Nice Find.
I like it.:metal:
Going to research the site now.:ito:

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It is full of good stuff. I have been following their wiring stuff for years. My 71 and ramp truck are pretty much done like they say.

The 68 I sold had a full on swap on it to this. :chevy:

So if you hit the Horn, do the Fans and Head Lights go on too?

That "new system" diagram is lacking. Previous poster has the right idea. Only one fan will receive power unless you are honking the horn. Looks like a recipe for complete frustration for a wiring novice.

You are technically correct but you have to remember this is wrote for cars & trucks of the 60's and earlier. They used the horn relay as a distribution block also out on the radiator support. But yes after you mentioned it they didn't do such a good drawing of the hook up. So yes that part should not been used for a vehicle that doesn't use the relay as a distribution block.
The earlier trucks though should be the same as the cars but I don't have one to verify by. I'm not even sure when GM went to the under dash horn relay in the trucks. I know my 71 has it.

Here is a new schematic I just did, deleting the horn relay part. The alternator doesn't show the other wires for a internal regulator alternator but they wouldn't change if you have already upgraded. The first two drawings show how it's wired without jumping the old regulator. Lot nicer than that gob of wires out on the support.
The wires are shown here for the 12SI alternator.
I'm not 100% on the solenoid on a later 70 model either but it may be better for the older 60 models. :chevy:

http://67-72chevytrucks.com/vboard/a...1&d=1580502981

http://67-72chevytrucks.com/vboard/a...1&d=1580502981

What the diagram fails to show and studying it will reveal, is that it is a copy of the 1966 and prior vehicles. The relays and other wiring use the horn relay as a primary junction and their connections have nothing to do with the horn function, Note the large red wire from the alternator. This wire is hot at all times so If it was tied to the horn it would honk constantly.

Here is a picture that better illustrates the issue. Note that the two terminals on the right end of the relay are separated from the horn terminals as I stated above.

Attachment 2054575

Andy -- My '67 K/10 Suburban has the same Horn Relay on the cab firewall as the '68 C/10 and '71 Jimmy. I had a rebuilder's manual for the Triple Nickel Chevy Sedans, but I sold it to my mechanic whose other customer had a '57 BelAir. I remembered how similar the wiring schematic and especially color codes were to the '68 C/10's.

Quote:

Originally Posted by '68OrangeSunshine (Post 8821494)

Yep my 64 SS Impala has the horn & D-bar still in it. But I have upgraded it to a late model alternator. The main point of this post was to show people how easy it is to make a good system even better. :chevy: