I have a 91 vert with turbo swap (thanks 7dust). I've had issues with the bright lights and wipers which I've fixed. The horn however is kicking my butt all over. I've replace the cpu with a brand new one jumped the GrWh and GrR and the horns do in fact sound. After searching and searching and searching some more I've come across one bit of info. I seem to be missing the wire assembly that actually touches the backside of the steering wheel. where does that wire go and what do I need to do to complete the circuit.

 

Not much help here, but.............if the green/orange wire at the CPU plug does not show it being grounded when you press the horn button, then the horn won't honk. But you know that.

The wiring diagram shows the g/o wire is part of the front harness and as a single wire, connects to a single wire connector (F-11) that in turn connects to a green/red wire that runs to the horn switch. Jpg attached. Sorry, don't know any more than that. Never had to mess with that part of the horns 'cause that part always put a gnd on my CPU. That's if the car has airbags.

IF no airbag, then F-11 does not exist and you have to look for the F-02 which is a eight socket plug shown in the left of the attached jpg.

 

I know its not being grounded cause there's nothing from the horn switch to ground. I just need to find a way to put a contact on to the ring around the back of the steering wheel. I'm almost positive that when that's done the horns will work.

 

You've seen the jpgs attached before I suppose. Items four and five are the items that cause the horn to honk when the buttons are pressed. I'm just getting up to speed on this part of the horns working. Seems when 4 is pushed that makes a gnd to be put on the six socket plug (the HO socket) shown in the jpg.

 

Are you using the O.E.M steering wheel? With the O.E.M. steering wheel (w/ airbag 7's), the wires that go through the clock spring and into the steering wheel carry the horn cable. It is then grounded on the steering wheel itself when you touch the button.

If you put an aftermarket steering wheel, you will have to ground out the wire on the ring on the aftermarket steering wheel hub somehow. I had to set up some interesting stuff since my hub didn't quite fit properly... The pictures hailers show are for a non-airbag 7. The #4 screw makes contact on the metal ring on the hub of your steering wheel. And the cable "signal" goes through that screw I believe. When you push the horn button you complete the circuit to ground.

 

my vert is no longer an airbag car. hasn't been since before I bought it. that being said it does have an OEM wheel from a non airbag FC.

What I've been looking for was what actually made the contact to the wheel. Thank you Hailers. no I gotta find someplace to get the contact and spring. Stupid TX laws and inspections requiring a horn.

 

Maybe, maybe you could buy a button type switch and mount it near the steering wheel? And somehow run a wire from the new switch to the green/orange wire that goes to the CPU and then get another new wire who's one end goes to a ground/chassis and the other end of that wire to the button type switch. Press button puts a gnd on the green/orange and the horn honks?

 

The way i got around this, I made a bracket and removed the old clock spring that sits behind the steering wheel. If you still have the clock spring, you can keep it but you will have to grind down the hub to allow the section where the wires are to go through the hub, if you are missing the clock spring, the wires will be down in the dash right under the steering wheel (in the pocket right below it):

http://www.miata.net/garage/momo/momowheel.htm

Otherwise, the bracket method i used. I made a bracket that uses the screws where the clock spring was held. Then, I used a spring and a brass screw and soldered the horn wire (I believe its the red/orange one if I remember right...) and mounted the screw on the bracket using a hole which is very tall to support the screw (you could make it thread into the bracket, it will be easier). So basically now the screw makes constant contact on the back of the steering hub by the spring force and the screw is only held there by the hub pushing the screw down into the bracket I made.

If you still have the airbag light on, you will need to use a resistor 10ohm or 3ohm resistor (try both, I forgot which one is in the car right now) and plug it in somehow into the two contacts on the blue harness....