Currently trying to test my horns; connected a wire from positive terminal on a car battery to the male plug on the driver’s side horn and nothing is happening (same on passenger side horn). My understanding is the horns are grounded via the bolts that attach them to the body so I don’t think that’s the issue. See pic to see the connection.

Thanks

 

FWIW, both horns on my 50k mile '87 were bad when I got it. They looked pristine, but neither worked. I replaced them with generic equivalents.

 

The horn circuit is grounded through the steering wheel. On my car there are two connectors to them. Also the frontmost fuse in the engine bay LHS fuses the horn circuit, in addition to the main fuse box inside the car. This is not shown on the factory circuit diagram!

 

I would think you will find a horn relay witch is controlled by the connector in the steering column. It is placed on the inside left wing below the light fusese. It is supposed to be covered by a plastic cover. just in front of the expansion tank.
Mine was stuck and needed changing.

 

I believe he's trying to test each horn itself with 12v directly applied to the horn terminals. The rest of the circuit can be tested with a multimeter or test light at the horn connectors.

 

That's correct; am I doing it properly though? I'm grounding the horns by just clamping a wire on the horn bracket and connecting to an unpainted body bolt.

 

Yes, but check for continuity between that bolt and a known good ground.

 

Very strange. Tested horns by sending 12v to the 30/51 post on the horn wiring diagram and got nothing, but when we sent 12v to the 87 post they work fine. See video below for better explanation where I actually show the wiring diagram and explain.


And here’s a picture of the plug.

 

Sounds a bit strange. You could test the relay by supplying 12v + and - to 84 and 85. You should hear clicking in the relay. If you measure the Ohm between 30 and 87 you should have 0 Ohm when you apply the power.
if that is correct you should test the cables connected to the relay. The brown is +12v and the purpleyellow is supplying 12 V to the horns when relay is activated. I understand the horns Are working. The other two cables gren and purple is going to the horn button inside the steering column. Green is +12V. The purple goes to switch and will be negative side of relay when horn button is pressed. ignition switch must be on to get power to horn button. Check the cables on the connector that brown is going to 87. And purple yellow to 30.
Hope this will help to get you a bit furter.
​​​​​​…….Anders

 

Thanks, I’ll give that a try tonight. You mention 84 and 85 - there isn’t an 84, so do you mean 85 & 86?

 

yes. Sorry . My fault. 85 and 86 is the coil in the relay.