View Full Version : Trouble Shooting Horn Relay
mark67ss Nov 30th, 06, 11:26 AM Well I am trying to trouble shoot a horn problem and here it goes.
My horn doesnt work. So I look under the hood and both horns are missing. Luckly I have an extra set so I connect them. I want to test the horns so I put a wire from the battery to each horn... they work.. Next I push the button on the steering wheel but nothing. So I pull the button off and there is no horn wire lead so I go and get one. I hook it up and push but alas no horn. So now I am thinking one of two things, The horn relay or a cut wire somewhere along the path from the button to the relay.
So here is where I am at. I have got a diagram of the horn relay and know this. Dark green wire goes to the horn, Black wire goes to horn button, Big red wire goes to 12 volts in the main splice and black pink wire goes to key buzzer, the last red fused link wire comes from the main feed on the fuse panel. So how do I go about trouble shooting this? Can I disconnect the black wire then ground that terminal to the frame to see if it makes the relay work? Will that prove anything?
Thanks
Mark
TOOFUN
Brian Lewis Nov 30th, 06, 04:16 PM Ground the wire and see if the horn blows, the horn relay should be clicking, you can check the horn relay by using a good 14 gauge ground wire from a good ground to the brown lead running to the horn relay, if horns still don't blow check the passenger fender ground and connection from horns to brackets for a good ground.
As for the steering wheel, if everything blows by grounding that wire then the wire hooks to whatever plate that needs to FLOAT above the wheel usually by a spring, when you push the horn button, it grounds the floating metal that has the wire hooked to it to the steering wheel which is ground, thus causing the horn relay to send a 12V to the horns.
The horn wire you linked to makes contact in a plastic container behind the steering wheel bracket that bolts to the column with a spaded connection. While it sits in this plastic container the other end should have a 1" long brass cylinder that is pressed against a circular brass grounding plate, thus you push the horn, ground wire goes thru cylinder to circular brass grounding plate which in turn connects to the brown lead on your horn relay near the radiator.
Sometimes people dump a few of these parts when they take the columns apart. I also found on my 63 nova the previous owners cut the horn relay under the dash in two places! I had to resolder both just to get a completed circuit to the horn relay under the hood.
mark67ss Dec 1st, 06, 05:49 AM Thanks for the info . Here is what I found out so far.
1. The relay is toast!! I disconnected it to try and clean all the connections and when I did I could smell a faint burnt smell. When I took the cover off the relay the smell got real bad. The coil winding has a dark ring right in the middle of the windings and smells burnt. The contacts themselves look excellent so I am assuming that there was not a short, just a burnt out coil! I am replacing the relay today.
2. This car is equipt with a billet specialties wheel. When I took the horn button off I noticed that there was no wire lead on the button, just a ground wire. I know it needs both since the tab is on the horn button for this reason. To set my curiousity at rest I took the rest of the pieces off down to the contact ring. Once the contact ring was off I was left with a round white plastic part with wires attached to it that lead down to the steering wheel. The turn signal contacts are there and work PERFECT(key power on tried it out) But I ran into a slight problem there and here is where I am stuck. There is a brass little tube that sits in the plastic piece. I am guessing that this is the part that the CONTACT RING stays contacted with. The problem is this part is stuck in. If I pull it up it stays up but will slide right back down if I touch it. Is this piece suppose to be spring loaded? I think in its present place it does not make contact with the contact ring above it. If this is the case how do I fix this?? Again I want to thank you for answering my question and helping me with this problem.
Mark
TOOFUN
Everett#2390 Dec 1st, 06, 06:09 AM Yes, the plunger is spring loaded.
mark67ss Dec 1st, 06, 06:41 AM So if its spring loaded it should be in the "up" position when the contact ring is removed? If so, how do I fix this? Is there something I can buy to fix it or do I need to replace the entire Turn Signal Switch Assembly?
Thanks
Mark
TOOFUN
JimM Dec 1st, 06, 07:18 AM The black wire from the horn relay to the steering wheel horn button is an "active low vircuit" The horn button GROUNDS the black wire to comeplete the circuit, energize the relay, and blow the horn.
I would guess that your relay burned out because the horn button was "pushed" all the time.
On most aftermarket wheels, the "contactor ring" (which the black wire is attached to) floats on 3 shouldered screws (which also secure the wheel to the hub). It clips onto the button when you push the button on. There should be a spring, one end rests on the end of the column, the other end pushes the button OUT so the horn only blows when the button is pushed. Sounds like the spring is missing.
mark67ss Dec 1st, 06, 08:10 AM OK,
I understand, but still have one more question. Should the brass plunger on the Turn Signal switch assembly be in constant contact with the contact ring above it? My aftermarket horn button floats and is internally spring loaded. When I push it, three screws project out of it and make contact to the metal adaptor below it. I have attached a crude diagram of how the assembly is laid out. You can view it via this link. http://new.photos.yahoo.com/draggingmedowntoo/album/576460762357565517/photo/294928803839358672/0It is crude but explains how it is currently put together. I really think the problem is in that BRASS PIECE that sits in the turn signal assembly. Like I said before it sits in the down position and can freely go up and down like it is just sitting in there. I am assuming it should be spring loaded.
http://new.photos.yahoo.com/draggingmedowntoo/album/576460762357565517/photo/294928803839358672/0
Thanks
Mark
TOOFUN
Brian Lewis Dec 1st, 06, 08:32 AM There are two springs
1) Horn button itself
2) Brass Plunger
Yes the Brass Plunger should be pushed out of its 'plastic cavity' by the spring at all times, thus to allow it to make contact with the brass contact ring at all times, only the horn button is kept in a noncontact state until you push the button. I would think you could buy a spring pretty much anywhere to fit in that plastic cavity.
mark67ss Dec 1st, 06, 05:16 PM Hello,
Well I got it working. I installed the horn relay that was toast and put the ground terminal to a good ground to test it out and the horn worked. Then I connected the black ground wire from the steering column to it and put a jumper wire on the contact brass button in the column to ground and it beeped too. So then I was left with the daunting task to figure out why the plunger was not coming out of its plastic sleeve in the Turn signal switch assembly. I pulled it out and looked on the back side but there was no way into the plastic cavity. I figured I would just try to jimmy the plunger out and worse case scenario I buy another switch. Well it came out without much fuss and Lord behold there it was!! A BROKEN SPRING CRUMPLED UP IN A BALL in the plastic sleeve!! I could not believe that something SO SMALL could cause so much trouble!! Now all I had to do was find a SPRING that small!! After about ten minutes it hit me. I USED A SPRING OUT OF A PUSH BUTTON PEN!!! Cut it in half and it worked the nuts!!! I was so happy!! Reassembled everything and hit the horn. BEEEEEEPPP!!! Never been so happy to hear something that most just take for granted on a daily basis. Definately a different reaction to a horn sound. Usually when I hear the horn it is followed by my middle finger and some ranting and raving!! Anyways, back on track and onto the next trouble item on the list!! Thanks again to everyone for all your help. It was very much appreciated!!
Mark
TOOFUN
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