A/C wiring questionRef AIM UCP C60 E09 for 1966

[Don G.]

The horn relay show 8 wires on it 2 ground,3 on center post and 3 on end post .

The R12 wire in a/c harrness will not reach the end post as shown.

I think that the R12 wires connecto the starter along with the battery cable. An I see no wire in the new or old harrness that could connect to the Horn Relay. But as luck would have it the old harrness is damaged in the area of question.

I have looked in AIM manual 1963 thru 1967 and the 1966 Chassis Service Manual ST72and they all show the same horn relay wiring.

What is correct and is there a the correct wiring shown some where.

Thank you for the help.

[Rich P.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Don,

All A/C mid years I have worked on draw power from the horn relay with a forked right angle terminal. The only wire going to the starter is the ground. It has been several years since I wired a 66 A/C car but thats how I remember it. What terminal does your 12 gauge power wire have? If it is a fork it goes to the relay. They never used a fork terminal on a starter connector.

You also never mentioned if this is a new harness and who it's from.

Rich

[Don G.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

RICH

M y harrness dose not have forked terminal ,but has a eye terminal that would fit the starter.

This is my first time do this I hope that i am doing correctly.

thanks

[Rich P.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Don,

like I said it has been several years since I did a 66 67 (I just finished a 65 with the forked terminal). SO you are correct then It would go to the starter (Is it a 3/8" eylet?)

Rich

[Larry M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Don:

On my 1967 327/350 HP factory air car, I have six wires at the horn relay. Two small wires that plug in under the relay for the horns. One is power to the horn relay from the steering column and the other is power out to the horns.

On the horn relay "buss bar" I have three wires. One is a large diameter (10 or 12 gage) red power feed wire from the starter BAT terminal. A second 12 gage red wire goes to the AC blower motor for HI speed. There is an in-line fuse on this wire about 6 inches from the horn relay. I think the fuse is around 20 or 30 amp....need to check to be certain. A third wire that connects to the "buss bar" is a black fusible link that connects to a 12 or 14 gage red wire that supplies power to the rest of the car.

The horn relay is grounded through a screw into the radiator support. There is a sixth black wire that connects under this screw. Not certain exactly where this ones goes without additional research....but can find out if you need.

I believe 1966 cars are similar.

Larry

[Jack H.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

On my 1967 327/350 HP factory air car, I have six wires at the horn relay. Two small wires that plug in under the relay for the horns. One is power to the horn relay from the steering column and the other is power out to the horns.

Terminals on the bottom of the horn relay are: switched power out to the horn(s) and contact closure to ground through the steering column's horn button. Their function is denoted by the emboss on the cover of the relay: "H" = horn and "S" = switch. That's a Delco Remy convention for all horn relays...

On the horn relay "buss bar" I have three wires. One is a large diameter (10 or 12 gage) red power feed wire from the starter BAT terminal. A second 12 gage red wire goes to the AC blower motor for HI speed. There is an in-line fuse on this wire about 6 inches from the horn relay. I think the fuse is around 20 or 30 amp....need to check to be certain. A third wire that connects to the "buss bar" is a black fusible link that connects to a 12 or 14 gage red wire that supplies power to the rest of the car.

Yes, the side terminals provide an engine compartment B+ buss. Power from the engine harness connects here as well as 'aux' engine power circuits (charging system, max heater blower fan, optional A/C, Etc.). This buss is ALWAYS hot (regardless of ignition switch position), so appropriate caution is advised when making/checking connections.

The horn relay is grounded through a screw into the radiator support. There is a sixth black wire that connects under this screw. Not certain exactly where this ones goes without additional research....but can find out if you need.

While there IS a small jumper wire for ground, the horn relay doesn't need a discrete ground. It gets ground via the horn button in the steering column. The jumper wire is there for the convenience of the charging system's voltage regulator...

Try it some time... Take a horn relay to the bench, connect ONLY power to the side terminal, a horn or dummy load to the 'H' terminal, and a jumper wire to the power supply's ground from the 'S' terminal. The load should fire up each time you touch 'S' to ground!

I believe 1966 cars are similar.

Yes and no... 1967 was the first year Corvette used fuseable links in the engine compartment. Earlier cars won't exhibit the 'pregnant wire' silhouette on critical power lines that attach to the horn relay's side terminal, buss bar.

[John H.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

The small (20-ga. black/white) wire connected to the buss bar is a sense wire for the battery gauge.

DO NOT be mis-led by the drawing error on the factory wiring diagram that shows a ground wire connection to the buss bar (the '67 diagram shows the same error); the horn relay is grounded at its screw attachment to the radiator support.

Attaching a ground wire to the buss bar will result in a big arc and lots of smoke .

[Wayne M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

.....On the horn relay "buss bar" I have three wires. One is a large diameter (10 or 12 gage) red power feed wire from the starter BAT terminal. A second 12 gage red wire goes to the AC blower motor for HI speed. There is an in-line fuse on this wire about 6 inches from the horn relay. I think the fuse is around 20 or 30 amp....need to check to be certain. .....

The above really wasn't said by Jack H; Jack only repeated Larry's words without using the "open square bracket, slash, QUOTE, square bracket close" system, so it came out as if Jack was the author. (sorry)


Larry -- just to clarify a few of your points. I know you are referring to 1967, but I doubt they are much different than '66 or '65's, other than the addition of fusible links).

Yes, air cars (and '65 L78s) have a large 10 gauge red wire from the starter, direct to the horn relay.

Further on in your paragraph, rather than "horn relay" you probably meant to say that the in-line fuse is close to blower motor [ie. speed] relay (the 1116992, on the passenger side evaporator box). The in-line fuse is 30 amp, as is the inside fuse panel (2nd fuse down), and not the 10 amp shown on the panel for non-C60 cars.

[Larry M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Larry -- just to clarify a few of your points. I know you are referring to 1967, but I doubt they are much different than '66 or '65's, other than the addition of fusible links).

Yes, air cars (and '65 L78s) have a large 10 gauge red wire from the starter, direct to the horn relay.

Further on in your paragraph, rather than "horn relay" you probably meant to say that the in-line fuse is close to blower motor [ie. speed] relay (the 1116992, on the passenger side evaporator box). The in-line fuse is 30 amp, as is the inside fuse panel (2nd fuse down), and not the 10 amp shown on the panel for non-C60 cars.

Wayne:

The 10 gage red wire between the starter BAT terminal and the horn relay has a node or junction in it INSIDE THE HARNESS where the output from the alternator ties-in and also where the fusible link/sensing wire for the charging gauge ties-in. And not just in my car. My friends 1967 BENCHMARK AND TOP FLIGHT FACTORY AC car is the same way. I know this for certain because his junction connection corroded/failed and he had to unwrap the harness to fix. I personally witnessed this.

Regarding the location of the fuse holder, I stated it correctly. My 1967 factory air car has the fuse holder within 6 inches of the horn relay. I know that earlier years (1965 I believe) had it closest to the blower motor/relay. Not certain about 1966.

I hope the factory guys didn't wire mine backwards the day they built my car?? Regardless, it is where it is, and it works correctly. I guess that's all that matters. Let's see what other 1966/67 owners say. I would be interested.

Not that things couldn't be molested/changed over the last 42 years, but my car is a very low mile (26,000 mile) very original car in most all respects.

Larry

[Larry M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

The small (20-ga. black/white) wire connected to the buss bar is a sense wire for the battery gauge.

DO NOT be mis-led by the drawing error on the factory wiring diagram that shows a ground wire connection to the buss bar (the '67 diagram shows the same error); the horn relay is grounded at its screw attachment to the radiator support.

Attaching a ground wire to the buss bar will result in a big arc and lots of smoke .

John:

See my post to Wayne earlier.

On my car and others I have seen, the fusible link and sensing wire for the battery gauge is not attached to the horn relay 'buss bar". Instead, it is located at a node or junction block on the red 10 gage wire from the starter BAT terminal that is inside the wrapped wiring harness. The alternator output wire also ties-in at this node/junction.

This junction is about 8 inches from the horn relay.

There is also a black ground wire that connects under the horn relay attaching screw. I believe that this ground wire services many of the forward engine compartment grounding needs. It is clearly shown as an engine compartment "grounding network" on DR REBUILD's 1967 wiring diagram. I did not personally try to trace out everywhere it goes.

The wiring is very confusing since the GM schematic is not correct in this area. I have used DR REBUILD's diagram, the GM schematic (as best as I could), and my personal observations to figure out where everything connects. I think that I am reporting correctly.

Larry

[Wayne M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

......I hope the factory guys didn't wire mine (1967 C60) backwards the day they built my car?? Regardless, it is where it is, and it works correctly. I guess that's all that matters. Let's see what other 1966/67 owners say. I would be interested....

Larry -- maybe I should stay with '65s . I dug out a '66 Corvette engine comp't wiring diagram from the '66 Chevy Chassis service manual and the NON-C60 wiring diagram (couldn't find one for air cars) DOES show this massive node off the 10 gauge, into which branch the volt reg (20R), the horn relay (14R), alternator (10R), and under-dash (cabin) 12R. This means they are no longer using the horn relay as a BUS, and the 14R that connects there is only for horn power. I looked at an 837 relay I have hanging around and there's still the two screw attachments on (what looks like the same bus as on the earlier 824) with the left screw area stamped BAT, as is for the 824.

Like you, I'm waiting for other '66 air cars to reply.

[Larry M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Wayne:

For 1967, the AC wiring schematic is located in the HVAC Section 1. It is not with the rest of of the wiring schematics. The 1966 may be similar.

Armed with the GM schematics (which may or may not be totally correct for 1966 AC cars), plus a DR REBUILD 1966 color coded wiring diagram (which seems to be very correct for 1967 and can be purchased from the DR), and a little electrical knowledge, Don should hopefully be able to trace and connect/land all the wires correctly.

Larry

[Wayne M.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

...For 1967, the AC wiring schematic is located in the HVAC Section 1. It is not with the rest of of the wiring schematics. The 1966 may be similar....

Larry -- thanks, Section 1 of 1966 Chevrolet Service Manual (also Chevelle, Cevy II, and Corvette) is where I found it for the 1966 corvette w/C60. But I've pored over it and have to say it is EXACTLY the same as the 1965 diagram for the same. It shows 6 wires to the horn relay plus 2 for the horn activation. And it shows the in-line fuse very close to the blower motor and the '992' relay. The 10R shows no intermediate nodes.

Gettin' stranger by the moment --- '66 specialists please jump in .

[Randy S.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

Larry -- thanks, Section 1 of 1966 Chevrolet Service Manual (also Chevelle, Cevy II, and Corvette) is where I found it for the 1966 corvette w/C60. But I've pored over it and have to say it is EXACTLY the same as the 1965 diagram for the same. It shows 6 wires to the horn relay plus 2 for the horn activation. And it shows the in-line fuse very close to the blower motor and the '992' relay. The 10R shows no intermediate nodes.

Gettin' stranger by the moment --- '66 specialists please jump in .

Don, Wayne and others,

Not a 66 specialists but here is what I see on my 66 with C60. 5 wires total on horn relay not counting ground

On left is 2 wires from connector, black and green. Also a black wire grounded to radiator support

On center terminal of horn relay is #18 B&W (ammeter) and #12 red. The red wire goes into the taped harness within 6" and my guess it is the ign switch.

On the right is only the high speed blower and fuse. The fuse holder is close to the horn relay like 67's so I have always assumed this was incorrect. C60 E9 shows the hi speed blower on this terminal but the fuse holder near the relay.

No red wires from regulator and generator as shown on E9

Based on condition of fuse block and bulkhead connectors I believe this to be an original harness.

Randy

[Neil C.]

Re: A/C wiring questionRef AIM UCP C60 E09 for 1966

POWER to which A/C Components??? Only two that draw power are A/C Clutch Compressor Switch with Green Wire to pigtail at Compressor and Fan and or Fan Relays for Blower Motor??? Am I missing something else?? Thanks