Help with 66 horn issue please

[Donald H.]

I bought a driver 66 coupe last week and need to get some things fixed so that it will pass the Virginia DMV safety inspection. I'm working on the horns right now.

The horns will not work from the horn button. If I remove the horn button and horn contact, and then short from the steering shaft to the horn contact brush, the horns do not work. If I remove the steering wheel and short from the steering shaft to the turn signal switch, the horns work.

What I have found is that the horn contact brush is not making contact with the horn area on the turn signal switch. The cancelling cam bottoms out against the turn signal switch/upper bearing area before the brush makes contact.

Picture one is of the front side of the steering wheel assembly.
Picture two is of the back side.
Picture three is of the steering column and turn signal switch.

I was able to wrap a little tin foil around the horn contact brush on the back side, put the wheel assembly back on and short from the shaft to the horn contact brush and the horns work thus proving that there was a gap.

Can anyone of you C2 owners, particularly 66 see anything in the pictures or any other suggestions before I go out an start buying replacement parts?

By the way, bubba did a lot of work on the car in the past. Rather than go to a hardware store and buy some cheap #8-32 screws to hold the cancelling cam to the hub, he used some self tapping screw (picture 4). Fortunately it didn't damage the thread in the hub to bad.

[Timothy B.]

Re: Help with 66 horn issue please

Donald,

The brush should be spring loaded to make contact with the brass ring around the turn signal switch. There is a adjustment on the hub I think if it's like my 63. Using a ohm meter may help some in verifing the continunity of all parts.

I think ground travels through the switch and goes to ground through the contact, shaft and through the rag joint to frame. This energizes the horn relay and full 12 volts is then applied to horns. After all this it's supposed to make a sound like beep..

Machine screws with phillips head and attached star washer are available at home depot and I believe there are made by sems so they are probably close to what was used originally..

[Donald H.]

Re: Help with 66 horn issue please

Donald,

The brush should be spring loaded to make contact with the brass ring around the turn signal switch. There is a adjustment on the hub I think if it's like my 63. Using a ohm meter may help some in verifing the continunity of all parts.

I think ground travels through the switch and goes to ground through the contact, shaft and through the rag joint to frame. This energizes the horn relay and full 12 volts is then applied to horns. After all this it's supposed to make a sound like beep..

Machine screws with phillips head and attached star washer are available at home depot and I believe there are made by sems so they are probably close to what was used originally..

Tim,

I do have good continuity all the way through. I can tell that the horn contact brush does have a spring as I can push in both the bottom side and top side. The bottom end of the brush is just not touching the brass ring around the turn signal switch. I'll do some more looking, but there doesn't seem to be any way to adjust either the turn signal switch or the steering hub to get them closer together.

I'll keep looking to see if there is a way to solve the problem. I don't think my tin foil test would be good for long term!

I did go to home depot and get some #8-32 screws and star washers to attach the cancelling cam to the hub rather than use the self taping screws that were there when I started.

[Donald H.]

Re: Help with 66 horn issue please

Success

Bubba had installed the horn contact brush upside down. Found an article from Dave Zuberer with clear pictures of the hub with the brush installed. Took the cancelling cam off, pulled out the contact brush and reinstalled it from the top side of the hub and the horns work as they should.

I want to re-emphasize how important this forum is for folks like me who are new to vintage corvette repair/restoration. It is invaluable to have access to the archive and experts who have been through these issues many time before.

Now on to the windshield wipers

[Timothy B.]

Re: Help with 66 horn issue please

Glad you got it fixed, Donald..

[Doug L.]

Re: Help with 66 horn issue please

I have been trouble-shooting a similar problem. The contact button was out of my steering hub when I got the car. have been trying to determine which way to insert the contact button. It may have been Bubba that worked on your contact but the '64 shop manual has a diagram that shows the contact installed exactly the way it appears in your photo, inserted from the cancelling cam side. I've had people tell me it is inserted from the top of the hub but figured the shop manual was the most reliable source. Go figure.
Doug