[dpoltzer]

1971 Firebird: Complete restoration including all new wiring harnesses and a new horn relay. Also had the steering column rebuilt by an old pro that of course included a new turn signal switch. I used my GM shop manual which has eliminated the "relay" as the culprit. ie: unplugged the two wire connector (black and green) from the relay but the horn still sounds. I then unplugged the turn signal switch from the connector under the column (per the GM manual) and then put my test light from a 12volt source to the black wire from the T.S. switch and the test light did not light up. The manual says
"locate the black wire that is grounded or shorted that is going to the relay".
This is where I am stuck! Any suggestions on my next move? Thanks

[LATECH]

The black wire at the turn signal switch goes to the horn button.It controls the ground to the relay to energize it.

If it has a short to ground then it will tun on the relay.

To check it, simply hook the test light clip to the battery +, then probe the black wire. Then depress the horn button and the light should ligh to indicate the switch and circuit in the column is Okee dokee.

Somehow the horns are powered up when they should not be.

The dark green wire is the power+12 v feed to the horns and they are self grounding.

connect the test light to the green for the horns.It should light up (unplug the horns to save your ears) then go and look for any green wire that is connected and unhook it.see if the light goes out.

The temp gauge is a green wire. (lighter green) maybe the horns are hooked to it. Just a thought.

Horn relay shows to have 4 connectors. Is this your relay?
https://www.firebirdcentral.com/1970...p/ste-2112.htm

[LATECH]

Scratch the info in my post. Yourcar has a relay/key in ignition buzzer setup and wiring /colors are different..and it is configured differently than an older poncho
Post a wiring diagram if you can.

[LATECH]

.................

[dpoltzer]

Thanks. The picture of the relay that you posted is the one that I have in my car. If the relay is mounted to firewall: Looking from radiator at the relay mounted to firewall: far right is Black with Pink stripe, center is orange and then one black and one green in to a dual connector to far left. My car is a 1971.

[LATECH]

The green and black are in the right spot as they are in a asymmetrical shaped plug in and only fit one way.The other 2 may be mixed up
Best to check it out before switching wires.Hold on a few

[LATECH]

when you have it hooked up and the horn is honking, try unplugging the connector with the green wire and black wire in it.Listen for the "click" of the relay.
If the relay is clicking then it could be the ground path the black wire provides.

It could be shorted.That would keep the relay on and honk the horns.

To check the black wire,unplug the connector, hook the test light clip to the battery positive and probe the black wire.If it lights , then it is grounded.Either it has a short, or the horn button is shorting out to ground.

power is supplied to the horn relay and the electromagnetic coil is switched on and off by controlling the ground path.The column switch does that. If the black wire is shorted, to ground, it will keep the relay on , honking the horn

[Peter Serio]

Those 1970s cars make use of the horn relay to serve 2 functions, a normal horn relay (same as prior year GM cars) also a key in steering column, ignition switch alert buzzer. So instead of a 3 wire plug-in there's 4. Also I believe that the metal tab on the 4 wire type relay to the firewall needs to be to ground.


You say that you've replaced all the car's wiring. You do not say what brand of wiring. If it is the plug-in type (direct GM-car replacement) or the kind you have to make all the long run ends but there is a possibility that there is a mistake in the new harness. I am not saying they are all bad but human error can happen.

[dpoltzer]

All of the wiring Harnesses are from American Auto Electric. I have used their products for 10 years now and have never had a problem. I will conduct that test that Latech suggested and will get back to you in a few days.Thanks again Gents.

[dpoltzer]

I have removed the steering wheel and the horn button and the horn still honks. I even removed the small horn spring and related plunger and the horn still honks. Don't know if this helps the diagnosis?

[unruhjonny]

/\ to me, this points to an obvious short, which to me eliminates the column wiring.
Have you followed the suggestions in post #7?
That seemed like a grat starting point.

[dpoltzer]

I will conduct the test from post 7 in a few days when I am back in town. Thanks again.

[Mickey_London]

You could try using two pieces of wire
Make sure your 12v feed wire ( orange on your car, mine was red ) is connected to the relay


Unplug the 2 connectors ( green one and black one ) from the relay
You can also unplug the black/pink wire, if you want, for this test

In this order put one piece of wire to the black terminal on the relay and then down to the horn sounder
Then with the other piece connect that to the green terminal on the relay
Now when you short this wire to ground the horn should sound
Your relay is good and your original wiring is either shorting out or incorrect

If your horn sounds as soon as you connect up the piece of wire from the black connector to you horn sounder then your relay has stuck on

Relay does not need to be earthed to the bulkhead for it to work

This is the problem I had
Hope you find the problem soon
Mick

[Old Goat 67]

UHHHHH......Everyone is guessing.

No one knows how the relay is configured.
Time to open the can and see what is connected to the coil and what is connected to the contacts. Could be hooked up to a set of break contacts that never operate!

These are NOT a given! All different.

["QUICK-SILVER"]

Originally Posted by dpoltzer

I used my GM shop manual which has eliminated the "relay" as the culprit. ie: unplugged the two wire connector (black and green) from the relay but the horn still sounds.

That test did everything but eliminate the relay.

The horn should NOT blow with any two wires unplugged from the relay.

Clay

[LATECH]

Green wire goes to horns from relay to horns.

If the horn honks with THAT unplugged then something is wired wrong

Not guessing here , I double checked the relay configuration after my first post.

If you unplug the horn feed and they still honk, then they are wired to something else, or a wire is crossed or tied into another live wire

Sounds like maybe, And i say Maybe the horn lead is wired to a hot source, like the coolant temp gauge wire which incidently is also green.

This is a pretty interesting problem.

My cousins firebird had the front markers wire wrong.Brand new harness.

Seems they had the side markers and the running lights tied together wrong.

I rewired the whole car front to rear with a new harness.(4 sections) Made the change for the front markers and added a 12 gauge feed for the HEI and removed the resistor wire to make it a clean install.
Everything worked perfect when done.Got a 55 inch led TV out of the deal. Woohoo

[LATECH]

..........wont let me post relay schematic

scroll down the page after opening and you will see the mechanical and electrical schematic of the relay

https://firstgenfirebird.org/forums/...&Number=312873


Looks like (late 68 ) 68-73 is the same

[Old Goat 67]

TYPICAL, but is it actual?

[LATECH]

Do you know what else it could be?

[Old Goat 67]

I am not trolling, just sugesting.