Why do you want to do that?  A positive contact produces a lot of arcing and burning of contacts.  I  'spose if you did it with a relay, it wouldn't be so bad.  Butt, I have already done enough re-wiring and my stock horn works just fine so I don't see a need to re-invent the wheel.

boomyal wrote:

Why do you want to do that?  A positive contact produces a lot of arcing and burning of contacts.  I  'spose if you did it with a relay, it wouldn't be so bad.  Butt, I have already done enough re-wiring and my stock horn works just fine so I don't see a need to re-invent the wheel.

"Once up on a time....when I was at band camp...."
No really, when I went to one of the MSBB's'  one of the horn contacts under the wheel broke and shorted to ground. The dash lights went out...started smoking under the dash....lights went OUT and other stuff I don't want to remember. Naturally this happened at night about 800 miles from home!
It may never happen again but..... if it had happened ANYWHERE else I would have been screeewed.
I just like to "improve" stuff  especially after an "uh-oh" happens. Call it... being-a-little-girl...over-reacting...re-inventing-the-wheel....liking-to-do-stuff-to-my-hobby....whatever!   If it helps somebody else that's a benefit too.
Besides......I'm sorta tired of reading  about..... brakes...power steering...and clutch cables.
Horn mods is just a subject change....
6s6
 

6sally6 wrote:

    ........I'm sorta tired of reading  about..... brakes...power steering...and clutch cables.

6s6
 

A huge Roger on that one!  
 

Last edited by boomyal (3/15/2016 10:52 AM)

Bullet Bob wrote:

6sally6 wrote:

Maybe you could post a drawing of how you modified your horn circuit so it's NOT always hot...just when the button is smashed.
 You've told me several time butt-chew know a picture is worth a 1000 words!
6s6 
 

The issue Mike is concerned about happens sometimes if an aftermarket horn switch shorts...which, I understand, is not terribly uncommon.  When this happens with stock horn wiring the circuit breaker in the headlight switch constantly trips and resets which, at night, can be annoying to say the least.

I'll post a drawing if and when I get an extra few minutes butt (TS&T) here's a simple instruction that is good for 65/66 and other than maybe the wire #, will work through 73:

1. Cut yellow wire (#460) that runs from the HL switch to the steering column somewhere near midpoint.
2. Tape off the end coming from the HL switch so it can NEVER touch chassis ground.
3. Install a ring terminal on the end from the column and connect it to ground.
4. Install a Bosch type automotive relay in a convenient location near the left main lighting harness.
5. Cut the blue horn wire (in the left under-hood harness) near the new relay.
6. Connect the end coming from the firewall to pin 85 of the relay.
7. Connect the end going to the horns to pin 87 of the relay.
8. Connect a short jumper (wire) from pin 86 to pin 30 of the relay.
9. Connect a FUSED hot source from the solenoid, battery, voltage regulator, etc. to pin 30 of the relay (second wire on pin 30, plan ahead)  THIS WIRE MUST BE FUSED (20A or so) AS CLOSE TO
THE SOURCE AS POSSIBLE.

Now when you mash the horn button you are applying ground to the relay coil and the horn honks.  If the horn circuit shorts to ground the horn will honk but the lights will be unaffected.  Simply pulling the horn fuse (Installed in step 9) or removing the relay will solve the annoying problem until you can make a permanent fix.

Why Ford installed a relay on the Falcon horns but not on the Mustang is beyond me...just another "Better Idea" I guess.

BB
 

 
Bob,

You have inadvertantly highlighted maybe the main reason a non-electrically trained hobbyist has so much difficulty troubleshooting electrical problems on these old Mustangs: sometimes the power is switched, sometimes the ground is switched. It's hard enough for those of us with training, just imagine how confusing this would be to someone trained as say, a welder.

Again thanks. This all makes good since and I will add the relay. Because I could not find the short. I think that I may have had reinstalled the TS incorrectly when I replaced the column bearing, There is just no sign of chafing that I can find and the problem is gone. I will much prefer a grounding short. I am going to look closer at the brake wire that goes in there because this problem started when I was pulling into stop the car or rolling out of the drive. Then I started to see it on the gauge, I wish I could re duplicate it now. 
Chris

Dang Chris, that's excellent.  I never thought of doing it that way.  It keeps everything looking stock out front.  I was taking the horn load off of the HL switch but it really isn't necessary...I mean, how often do you use the horns? 
That's what I love about this forum, always someone with a different approach.  Again, excellent idea, Chris.   Thanks.

BB1

6sally6 wrote:

Besides......I'm sorta tired of reading  about..... brakes...power steering...and clutch cables.
Horn mods is just a subject change....
6s6

Maybe it's time to start posting about open headers, excessive noise and burnouts

You'd fit right in down here Chris.
https://www.youtube.com/watch?v=tI2E7Mq7F4A

LOL