'66 390hyp w A/C wiring

[Jeremy Hedges]

I am getting a '66 390hp with A/C back together and have a few wiring questions. First of all the horn relay wiring only has one "Fork" wire going to it, it is the red wire that goes under the screw on the left. There are two others that plug into the bottom, but this is not another wire to go under the right hand screw. Is this corrrect? Second, the harness that goes thru the firewall to the A/C outer box, the one that connects tot he relays and fan, there is a red wire and a black wire, both with round connectors, like a bolt would go thru. They look as though they go to the starter. Red on solinoid, black on starter mount bolt to block? And on the engine forward harness of course there are there are the same two wires, connectors and colors are the same. I have found that with an A/C car, some of the connectors on a non A/C car are just taped back. Do I connect both red and both black wires to the starter and starter ground? Or do I not use the black and red wires from the forward engine harness? Please advise. Scematic is not clear to me on this.

Thanks
Jeremy Hedges
#31711

[Jack H.]

Re: '66 390hyp w A/C wiring

I've not heard the term 'fork wire' before, so I presume this is something you made up to refer to wires that terminate with a tongue style spade lug connector. The screw terminals on the side of the horn relay accept this style of connector.

There are two screw terminals on the horn relay and they're connected together. This is where B+ line(s) connect (+12 VDC) and, depending on the car's option configuration, there may be more than one wire connected here...

[Jeremy Hedges]

Re: '66 390hyp w A/C wiring

The car has A/C, PB, PW should there be one or two terminals connected?

Jeremy Hedges
#31711

[Jack H.]

Re: '66 390hyp w A/C wiring

Consult your copy of the '66 AIM. I don't have one, but the '65 harness wires similarly even though a different PN horn relay is used...

In the electrical section of the AIM, you should find the base car's wiring called out with respect to the horn relay. In '65 it's done under UPC-12, Sheet A8 where there's a discrete 'View A' blow up of the horn relay showing two circuits connecting to the horn relay's side terminal buss bar.

One connection is a set of red wires that provide power from the battery/starter. The other connection is a set of B/W wires that introduce the charging system (alternator & voltage regulator).

Pay special attention to the blown up drawing and you'll see two discrete ground wires being connected to the horn relay's mounting tab. Since the relay bolts to the fiberglass inner fender, these ground wires are REQUIRED to make the relay function!!!

Last, flip to the option section at the rear of the AIM and look up the additional changes introduced by C-60 (air conditioning). There, you'll find the wiring called out in the 'E Sheets' of the C60 option and see the special provision for the AC blower fan taking its max speed power wire from the horn relay's side terminal buss bar...