Horn does not work

[camarojim]

Hello new to this site just bought my daughter her first vehicle she wanted an old Chevy Truck. I found a 1966 C 10 Fleet side Very Minor rust runs great looks good not perfect but very clean she had wanted a truck that she could learn about repairing and what makes them tick something that she could work on with me as a father daughter project. when we bought it i knew the horn did not work so i figured we could start there. the truck has been converted to a alternator with a built in voltage regulator. So the stock voltage regulator is disconnected the horn relay ties into the connector of the stock voltage regulator. Has someone out there converted their truck to a alternator and had this wiring setup that they got their horn to work i did not install the alternator so i am a little lost i got shop manuals on the way they are just not here yet. thanks in advance for any help anyone can give me.

[ACK]

The FAQ section has articles with pics on converting to an internally regulated alternator. I would start there and see if the alternator and relay were wired correctly when the PO made the change. If it is, do you hear a click from the relay when you hit the horn? If yes, then I would guess the horn or the wiring to it is the culprit. Good luck!

[camarojim]

OK i will do some research in the FAQ section i will keep everyone up to date as i find something out thank you for the responce the more i think about it the more puzzeled i get.

[AnlaufJohn]

Great to hear you have a child who is interested in old Detroit Iron.
As far as I can remember, when I switched over from the old Delcotron generator to a 10SI alternator, the horn wire (green with female terminal) wasn't disturbed at all. You may have it floating around in the area, but there really isn't any reason to mess with the horn wire.
The horn relay is a point of 12V power distribution to other parts under the hood.
A great resource is a single page, laminated wiring diagram from
www.classiccarwiring.com. I have been using mine for 4 or 5 years now and it helps with understanding a clump of colored wires and what they do.
Good luck,
John

[jtrichard]

get your voltage test light out or volt meter one terminal on the horn relay should have voltage (12+) one other goes to the horn and the other goes to the horn button if you have voltage and the wire is there that goes to the horn ground the other terminal out and you should have a lot of noise if not check for voltage on the horn terminal while grounding the button terminal if none listen for clicking in the relay as you ground it if no clicking you need a relay ....if clicking but no voltage to horn lead you need a relay if you have voltage to the horn lead then you need a new wire to horn or a new horn ...if when grounding the terminal the horn works then you need to pull the horn button and clean the contact spring plate when you pull the button and remove the 3 screws there will be a brass contact ground that out and see if you have noise if so start cleaning if not you have an open wire to the relay

[TJ's Chevy]

Check your grounds as well. Also clean up the area were the horn sits. Scrub the horn bracket and the radiator support panel ware it is bolted to. Believe it or not the horn is grounded there also as far as I know. Cool that you daughter likes old iron! T.J.

[camarojim]

Well i found a wiring diagram here in the FAQ section and some tips from you guys on testing the relay got my wiring straightened out with the voltage regulator. tested the relay it was bad installed a new relay still did not work with the horn button did the test with the new relay horn works. dissemble horn button and i think there is a part missing. i have a cup rubber seal to the button and a plastic ring with three holes in it. and that is it i see some kits have a contact plate but they list the year for the kit as a 67 does a 66 have a contact plate? Also i found that the back of the contact pin has been sheared off so it is flush with the plastic. and finally down on the turn signal cam where the wire for the horn comes in there is no way for ther contact pin to engage it because the wire and it's connector are a good 1/4 of an inch below the top surface of the turn signal cam. i ran a jumper from the steering shaft to the wire on the signal cam and the horn works. So does a 66 have a contact plate if so does it install under the cup? Thanks again for all your help. And soory for the delay was not able to get at it right away due to rain.