Troubleshooting Horns

Let's see... my original post on trouble-shooting my horns was on July 31... what the hell have I been doing. Actually, I tool Looney's advice for a while, and just said "who needs a horn", and I just drove and enjoyed the car while the weather held up. Then it got cold, and I had no heat in the garage. But I finally broke down and bought a 75k btu gas heater while it was on sale at Menards. So today it's 25* outside, 35mph winds, and snow flakes are going by sideways, and the thermostat in the garage reads 60*. WHOO-HOO!

I've been jones-ing to work on the handful of projects I have for the car before spring, and these horns are one of them.

So following postcar's advice, my first step was to try grounding the black wire terminal on the horn relay to the negative terminal on the battery. And happily I can report the horns honked, scaring the crap out of me the first time, since I had to rub the alligator clip on the terminal a bit to get a good connection... and I was sure I was electrocuted!

So now I need to go in search of the issue upstream.... in particular the grounding from the fender well all the way up to the horn buttons.

Question...
I'm guessing that the power for the horn relay is drawn directly from it's connection to the battery cable, and the black wire activates the relay, sending power to the horns through the green wire. So the fuse for the horns in the fuse box... is that just a part of the grounding circuit for the horn buttons? Or does the green wire go from the relay, through the fuse panel, and back to the horns? I don't think so, but need to understand where the fuse is in this whole circuit.

Ok... major advancement this afternoon. The horns work... or should I say horn.

Following the grounding from the relay back up the line to the horn buttons, I was able to verify continuity up to the horn buttons themselves. I was able to activate the horn by grounding the contact on the column-side of the contact plate using a small screwdriver grounded to the door switch/plunger. Beep... anemic... but at least beep.



Turns out the horn button contacts were not completing ground, either one of them. It appears that whoever I sourced the steering wheel center bar from, who included a set of contacts in the box, had perhaps cleaned them in a dip, or with some other sort of solvent. Whatever it was had left a film on the contact surfaces which prevented them from making metal to metal contact. I cleaned them with some 280 grit sandpaper, which left a white residue on the paper. Tested for continuity with success, re-installed the center bar assembly and we now get "Beep".



Most excellent... almost.

As I mentioned the Beep was pretty lame, and it turns out only one horn is beeping. I checked the wiring by swapping to the opposite horn, ruling out the wiring. I checked continuity from the horn bracket to the negative terminal of battery... check.

I tried banging the horn with a rubber mallet, in case something was froze up... ;D Na-da.

It looks like the horn halves are rivited together, so should I assume the horn is not a servicable item?

The horn that's not working has an "H" in a circle, and a small G (which I think is the note) centered over the Delco-Remy logo.



Does it make more sense to get a new one from Fusick, or source a used one from one of you guys?

Steve, I just went thru my horns last week. Tested, painted etc. From what Ive read any new or NOS horn you buy will not have the bracket on the back to mount them. Bracket is welded on.

They are rebuildable,

www.classiccarhorns.com/

179.00 to rebuild and restore. Not much more than new ones from Fusick. And they will be the same horns you sent out and will mount back on the core support correctly. At least you know they can be rebuilt so dont toss it.

Probably best bet is get one from one of us that you know works.

I should have a few, I`ll pick out a nice one if your interested.

But if you remember the pics I posted of the inner workings of a horn, there pretty straight forward. Did you try "gently" turning the adjustment screw? Back and forth about 1/4 to 1/2 turn while energized, to see if the points are out of adjustment or dirty.

I adjusted the screw through it's full range of adjustment and other than a slight "clunk" sound when energized, the horn made no other sounds.

At first I connected both a hot wire and ground directly to the battery, but I noticed the horn began to heat up pretty quickly, and I disconnected the ground. A little bit of smoke came out between the horn halves, so obviously you don't want to energize the horn for more than a second or so. So I would just make a small adjustment, energize the horn, and repeat. I did so throughout the full adjustment of the screw. So unless the adjustment is extremely fine, and I just missed the point that allows the horn to function, my horn is out of commission.

Do you think that there is a way to "un-stick" the points without cutting/grinding off the rivets to open it up? Not sure of anything else that could make it stick other than moisture that has things rusted up some. Could something like PB Blaster, or similar be sprayed into the opening to try to free things up and not damage other parts? Since the pictures you took are no longer visible in this post, I can't review it to see if there would be parts sensitive to the spray.

I read on a camaro forum about doing what you mention, WD40 down the throat of the horn. Guy said he did it to a non honker and the next day it worked. The horn rebuilders website says to definately not do that to a horn. He may want you to send them in instead of fixing it yourself. Who knows, cant hurt to try if its DOA.

I`m having a little late start here this morning, but if you`d like, when I get back from coffee I can re-post some pics of the inners of the horn so you`ll know where your aiming. Might even be a better way of getting some blaster where you need it.

Don`t think I`d use anything but WD40