Ok guys... This time I'm stumped.
Driving down the road. Honk once. Works great. 30 seconds later try again. Nothing happens. Get home, try again. Nothing. Figure it will work itself out (we all know how these issues are). Try it again tonight. Still nothing. Remove ground and reinstall (bolt headlights are mounted to which ground to frame. KNOW this is a great ground, plus it worked fine this morning). Still nothing. Remove and reinstall terminal nuts. Nothing. Removed horn button and jumped contacts with screw driver. Nothing... Checked conitnuity. All good. Horn, wires... Everything. Checked horn button voltage. 6V. I checked the horn and it got nothing with the horn button pressed? The terminals are a little rusty, but again, worked. Removed the horn. Tested direct. Nothing. Spun by hand and tried again. Nothing.
Once again, horn tests fine conitnuity wise.
No clue what's going on. It was working great one minute and not the next. Literally.
Looks mint under the cover. Already rebuilt it myself, oiled sponges, new gaskets, etc and was working great until this morning. Only thing I can think of is that it was raining yesterday and since it is in a top section hood only speedster... It's uncovered. However when the cover was removed it was all dry. Don't think the couple of drops of water that could get in there would affect anything.
I'm sure this is a simple issue.
Three things come to mind, two minor and one major.
There is a motor inside, with brushes. So possibility number one is a brush problem. It could be oil or dirt on the armature, or a brush that is broken or bound up so it can't press on the armature.
Possibility two concerns the way these horns are made. The motor turns a disc with bumps on it, which rubs against a screw or bump in the middle of the diaphragm. There could be a bad bearing in the motor, or something about the interaction between the disc and the bump in the diaphragm. See if it can be spun by hand, and follow up from there.
Possibility three is a broken wire somewhere inside the motor. That could be in the field or the armature, and could be anywhere from difficult to fix all the way to fatal.
Please let us know what you find as you hunt for the problem.
4th, some of these horns may have an adjustment ether at the disk on the diaphragm or pressing on the end of the armature shaft. If yours has one of these, may just have too much pressure. I know on Model A horns, sometimes just putting the cover on can change things.
Can spin by hand easily. Also I don't think it's too tight, it's only a couple clicks plus it was working before and it spins by hand very easily.
Would a broken wire give me good continuity as well through both terminals?
I'm thinking it's the commutator. I never cleaned it and it's dirty. I'm really hoping it's just that.... I'll clean it today.
Brushes appear fine. Not worn, in fact, they look like they were replaced whenever this was last used.
Clean the commutator and see where that gets you. A pink pencil eraser has always done a good job for me of cleaning electrical contacts.
Have you tried honking the horn with the cover removed? That would rule out whether it changes the tension on it or if the motor inside is somehow arcing to the case.
Yes, nothing moves when the cover is removed. Iveevn loosened the adjustment screw so there's no pressure on that ridged wheel so there's no load. Nothing at all. No Sparks, no movement. Nothing.
I'll try an eraser now but the commutator is shiny and again, there's continuity between both terminals.
Can't believe this just stopped working! >
Plus I'm also connecting it directly to the battery right now. The battery cranks the starter and lights work so I'd say it is good.
Alright folks. Think I've solved it.
Couple things that were a bit off.
First, the commutator, while shiny and copper just wasn't clean enough apparently. Used an eraser (thanks Tim) and cleaned it up. Connected it to the battery. It spun!
I excitedly mounted it back and hooked it up, pressed the button... And....
Took it off and connected it to the battery. Works great. So I made a new ground wire. Still nothing. Tested conitnuity and it was all good... I was puzzled... But then remember the other day when I tested this, it was getting 0 volts.
I removed the horn button cover and jumped the contacts. Still nothing! I then measured the voltage of the two contacts. 6V (well actually, 5.98). Then I kept it pressed down and measured the two horn terminals. 2 volts!
Now I am stumped again. This sounds like a wire with at least half of the strands broken inside to me, enough so 6V is not being passed through or something similar.
So then I flipped over the button for the heck of it and jumped the two terminal screws. The darn thing spun!
Something strange is going on with that old switch. Time to order a new one...
It's a cheap 70s or 80s plastic repro that bolts to the end of the old horn button mount. I guess corrosion and the metal being bent so much just took it's toll? Ah well, that button was ugly and has been on my replace list for a while anyways.
FYI, reading continuity thru a circuit doesn't mean it's 100% alright. You can have two ends of a broken wire still touching and read continuity thru them. Attempting to powering a high current device (ie: motor or lamps) thru the same wire will create the very situation you are facing.
We just got a got a quote on rewinding just the armature on a 12 volt Klaxon (some early cars like Dodge were 12 volt), in the ball part of $75.
Mine was doing the same thing and it ended up being wired with wire for 12v. Changed out with thicker wire and the problem was solved.
not T related, but wiring. My well pump quit working the other day; I was able to get it running again by tripping the pressure switch multiple times. OK, the pump is over 15 years old, so, figured it was due for replacement. Go down, buy new pump, pull old pump out of well (85 feet down). Carefully put on new pump,seal wiring, put in well and throw breaker back on. then hi the pressure switch--BAM! breaker throws. Hmm, figure new pump must be bad, so put old pump back on so we can have water for a while, Breaker throws.HMMM. connect new pump directly to pressure switch and throw switch, zoom! HMM, pull out pump again, can see nothing wrong with the wires, although they have been spliced multiple times.Go buy new well wire ($150). That solves the problem--still can't see anything wrong with old wires!!! OH WELL. . . (Pun intended)