Author Topic: Horn Relay? (Read 546 times)

daveSanborn · « **on:** March, 06, 2009, 06:20:52 PM »

I have no experience with the first generation cars and their horn relay.

With everything hooked up (minus the steering wheel), when I ground the contact switch on the steering column the horn relay "clicks" but I'm not getting any power out of either of the two wires leading to the horns. Does this indicate that the relay itself is bad?

Oddly, when I shoot power straight from the + battery terminal to either of the horns, neither of the horns honk, weird....

Maybe the horns themselves need a better ground where bolted to the radiator support?

I've only started the troubleshooting on this "last area" of the car's repairs, but I'd like to think that if the relay was working properly, my test light would illuminate when connected to one of the horn power wires while I was grounding the horn contact switch back on the column.

1964.5 car BTW with the generator removed. The Yellow wire that would normally route from the regulator to the relay is now a constant hot coming from the starter solenoid.

Any ideas?

Midlife · « **Reply #1 on:** March, 06, 2009, 06:28:36 PM »

First, let me state that I don't think 64.5 horns work any differently than the later years.

Secondly, there is no "horn relay". Power is supplied from either the fuse box, headlight switch, or other device to one side of the turn signal switch (yellow wire). By pressing the horn button, you make electrical contact between the two rings on the underside of the steering wheel so that voltage is now transferred to the blue/yellow wire that actually goes to the horns.

The fact that you can't energize the horn directly from the battery tells me that either you have a bad ground or the horn isn't buzzing. Yes, the ground comes from the bracketry, and you should scrape the paint on the radiator support near where the large screw attaches the bracket. You can further test the horn by taking the ground from the battery to the case. There's a small screw that you can move in and out on the horn diaphragm to make it buzz.

I've no idea what you are hearing about a click. If power is in the blue/yellow wire after connecting it to the yellow wire, then perhaps you've lost continuity at the connector at the base of the steering column. From there, the only other connector is the large firewall plug.

Hope this helps.

daveSanborn · « **Reply #2 on:** March, 06, 2009, 06:34:55 PM »

Hmmmm..... It definitely does help. I'll look at a few things tomorrow and report back.

Are you saying that the Blue/Yellow wire should have power? It doesn't. I'll start there I guess....

Thanks Mid!

daveSanborn · « **Reply #3 on:** March, 06, 2009, 06:43:07 PM »

Quote

Secondly, there is no "horn relay".

Well, this is why I asked here.... I'm holding in my hand the Jim Osborn wiring schematic book for 64.5 cars and it clearly shows a horn relay receiving power from the generator regulator. "Secondly" (LMAO), the horn relay is bolted to the radiator support just below the drivers side horn.

Midlife · « **Reply #4 on:** March, 07, 2009, 02:39:15 AM »

There is a horn relay for 64.5's (Note that I caveated my first response that I thought 64.5's were the same as 65/66's). It appears that the horn switch is normally grounded. When pressing it, you remove the ground, forcing the poor lil' electrons to find ground via the horns themselves, causing massive grief for the horns, which wail.

My advice for checking the individual horns via batteries and grounds holds (which bypasses the relay).

daveSanborn · « **Reply #5 on:** March, 07, 2009, 06:04:41 AM »

Quote

the horn switch is normally grounded. When pressing it, you remove the ground

Not having been out to the shop yet to continue troubleshooting, but the above statement makes a LOT more sense. I think now I know exactly how this system is supposed to work. Thanks Mid!

First order of business will be to establish good grounds for the horns themselves.

It's tasks like this one that make me wish I had a little helper around here. Engaging the steering columns spring loaded horn switch (that I now learned kills the normal ground)... and then checking for power at the radiator support mounted horn relay 6' away... is cumbersome. As usual I'll figure out a way to do it alone.

Thinking out loud now...

The steering columns horn switch is a small spring loaded plunger type switch. The contact tip of the plunger is probably in constant contact with a "collar" that attaches to the steering shaft. When the horn/collar is depressed, ground is lost as the switches contact recedes into the plunger. This collar is currently removed and the contact tip is touching nothing. With this said, the Blue/Yellow wire feeding the horn relay is NOT presently grounded. So the relay should seek ground through the horns themselves. But here's the rub, the power wire(s) going to each horn are not "hot" under these circumstances.... which leads me back to my original question/dilemma... the horn relay itself may be inoperative.

Desktop electrical troubleshooting.... you gotta love it.... not.

Sluggo · « **Reply #6 on:** March, 07, 2009, 06:37:10 AM »

Quote from: daveSanborn on March, 07, 2009, 06:04:41 AM

Not having been out to the shop yet to continue troubleshooting, but the above statement makes a LOT more sense. I think now I know exactly how this system is supposed to work. Thanks Mid!

First order of business will be to establish good grounds for the horns themselves.

It's tasks like this one that make me wish I had a little helper around here. Engaging the steering columns spring loaded horn switch (that I now learned kills the normal ground)... and then checking for power at the radiator support mounted horn relay 6' away... is cumbersome. As usual I'll figure out a way to do it alone.

Thinking out loud now...

The steering columns horn switch is a small spring loaded plunger type switch. The contact tip of the plunger is probably in constant contact with a "collar" that attaches to the steering shaft. When the horn/collar is depressed, ground is lost as the switches contact recedes into the plunger. This collar is currently removed and the contact tip is touching nothing. With this said, the Blue/Yellow wire feeding the horn relay is NOT presently grounded. So the relay should seek ground through the horns themselves. But here's the rub, the power wire(s) going to each horn are not "hot" under these circumstances.... which leads me back to my original question/dilemma... the horn relay itself may be inoperative.

Desktop electrical troubleshooting.... you gotta love it.... not.

Huh????

I don't have a diagram to look at but if you have a horn system that uses a relay and grounds where the horns mount to the core support the relay can't ground through the horns

The horn is grounded via it's mounting, so it needs power on the single terminal to function. That power has to be supplied by the relay.
If the relay clicks when you push the horn button the switch side of the circuit is working. It would also be safe to assume that the relay has proper ground.
If this is the case, you have eliminated everything from the relay back. You could have one of three problems.
1: Relay bad. even though it clicks on the switch side does not mean the pole inside is being contacted to send power to the output terminal.
2: Bad ground at horns.
3: Bad horns. Run a wire straight from power to the terminal and ground the horn bracket.

My Bet: Relay

daveSanborn · « **Reply #7 on:** March, 08, 2009, 06:07:21 PM »

The relay fixed it.

Sluggo, checkout the wiring schematic for the unique 64.5 horn wiring. The one wire on the steering column never has power, instead it's a ground wire. At least that's the way I read the schematic and during T/S of the system that wire never indicated "hot" with my test light.

Sluggo · « **Reply #8 on:** March, 08, 2009, 06:45:38 PM »

Send me a copy of it. The switch on the column supplies ground to the relay. It can't be hot because it would blow the fuse every time you short it to ground.

Midlife · « **Reply #9 on:** March, 09, 2009, 01:48:59 AM »

Could this relay be a floating relay? One that doesn't close until it sees a ground signal as a trigger? I didn't think that design was terribly reliable...

daveSanborn · « **Reply #10 on:** March, 09, 2009, 07:45:05 PM »

Quote

The switch on the column supplies ground to the relay.

[/i] [/b]

Exactly.

Sluggo · « **Reply #11 on:** March, 09, 2009, 08:39:00 PM »

Quote from: Midlife on March, 09, 2009, 01:48:59 AM

Could this relay be a floating relay? One that doesn't close until it sees a ground signal as a trigger? I didn't think that design was terribly reliable...

Prolly why it quit workin'....no? :pick