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My horn has never worked. A few weeks ago when I was working on the brake lights I replaced the turn signal switch: Turn Signal Switch | Dennis Carpenter Ford Restoration Parts pictured below, and both horn brush assemblies, Horn Blowing Ring Contact | Dennis Carpenter Ford Restoration Parts also below. That had no effect so today I changed the horn relay, https://www.rockauto.com/en/moreinfo...402568&jsn=449 I gave my horn button a quick press and out came glorious horn sound. Being so pleased with the angelic tone I pushed the horn again. Nothing. I got one short blast for my troubles. I unhooked the relay and jumped the connector with an amp meter, the horn sounded and it drew about 9 amp. I tried the continuity tester on the relay side of the connector and pushed down the horn button, nothing. Is there a way to test the horn brush assembly? Anything else I should check out? I'll bench test the relay later today. Thanks Repo turn signal switch I couldn't believe something so small was $6, and I needed two of them. Cheapest one available at rockauto
On my 64 the horn wire exits the firewall into the engine bay with a single bullet connector right there, so it was easy to split or isolate the lack of continuity to ground, to somewhere back inside the cab or under the steering wheel. On your 65 it may have a similar convenient spot to check, I dunno.
Turned out to be the lower brush finally wore out. Like you, was happy to have the horn back. Then out on the road one day it was inop again. Hey! WTF. So yanked the steering wheel yet again, futzed around with everything again etc., put it all back, M.O.C. ok.
Then about a week later, it stopped working again. Think I narrowed it down finally to the steering wheel itself not seated down on the column taper far enough. There is a specified torque of 35 ft. lbs for the steering nut but the factory must have routinely busted that spec by quite a lot. Don't strip it though! Check for continuity to ground on the horn wire while pressing the button, try reefing the wheel nut down a little bit at a time and sneak up on it.
Ted, thanks. I hadn't really given much thought to the steering wheel torque. I'll pull the wheel sometime this week and check out the brushes and the wire through the firewall.
BTW I bench tested both old and new relays the both worked as expected.
Yeah there maybe isn't much else, it's simple. For the lower brush contact use a drill bit or something as a stand in for test purposes and check for continuity to ground out to the engine bay. "Beep".... Ok, good. If not I suppose the turn signal mechanism could be at play but I doubt it.
The original copper brushes get tarnished and lead to intermittent, a little polishing helps with that. The lower brush contacts an aluminum ring on the wheel, clean all the gunk off that and maybe use a scotchbrite. Then a thin film of NO-OX or vaseline. Then check the air gap between the steering wheel and the shift column and if it maybe seems excessive. The brushes won't make enough tension to reliably contact if this is the case.
Good advice so far...
I want to add this: I recently discovered that my local electronics store sells a variety of carbon brushes with springs. Not sure if they offer an exact replacement, but the price is right - a buck each!
On a 1965 or 1966 with the rag joint you will need a ground strap across the rag joint. Some of the aftermarket ones don't have the ground strap and sometimes they fall off before they make it onto the truck.
Read this from Jo Wilker. He fashioned his own with a 3" piece of wire. Check for continuity across the rag joint. The ground comes up through the steering shaft. The column is grounded separately.
Not to be to obvious or presumptive, but I can't remember if there is also a fuse that the horn is tied into. I got my dash lights working the other day and of course the fuse blew shortly after... well, now I'm trying to figure out what caused it to over draw so I'm not just throwing fuses in every day. Thought that might be a relevant anecdote.
Here's an original style rag joint from my 1966. You can see the ground strap runs across from one pin to the other on one side and then to the right to the 3rd bolt which connects the "other" side. This is one of a few critical items to a working horn if your truck uses a rag joint.
The ground strap also acts as a natural stop for a maximum depth to set the steering gear shaft into the rag joint, but that's not necessarily going to make contact directly in all cases. Looking at the aftermarket ones on places like Amazon.com and others they often appear to not have this ground strap.
For bonus points - in Jo Wilker's post that I linked to above he says
"My horn went from not or barely blowing to working properly again when I added one. "
In his case....
Why would it work barely at times?
Chad
Why would it work barely at times? -- I don't know, intermittent contact on the rag joint? Chattering relay? Tell me more!
To close the loop on my issue, I pulled the steering wheel tonight and checked continuity from the "lower" horn brush (the one in the turn signal switch) to the relay (along the blue/yellow wire. I found that as I rotated the brush it was much "happier" in some positions than others, I left it where it had good continuity and buttoned it back up, using the torque spec recomended by Ted. While reassembling I cleaned up the ring in the steering wheel that the upper brush contacts. When it was all said and done the horn works fine now! It's a coincidence I have a new aftermarket rag joint in the mail so when I swap that on I'll just put in a jumper from the start.
If the ground doesn't come through the steering shaft then there is a path of some resistance from the column itself through the upper bearing and the metal bushing but there is some grease in there typically so contact would be intermittent at best. He might have found that turning the steering wheel back and forth while pressing the horn button made it work for a moment. Once Jo Wilker added the separate ground that made a new path of least resistance and fixed his issue.
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