Mazda Rotary Club

General => General Technical => I. C. E. & Electrical => Topic started by: lockwood77 on September 01, 2008, 11:12:32 AM

Title: Momo boss - how to get horn working!?
Post by: lockwood77 on September 01, 2008, 11:12:32 AM
OK, those of you with a Momo steering wheel boss, how do you get the horn working? My OEM wheel has a grooved circle and "finger" contacts on the back of the wheel to make the horn connection. The Momo boss has a flat plate of metal, so it will never make contact with the OEM horn connection.

Any ideas of the best way to fix it? :confused:
Title: Momo boss - how to get horn working!?
Post by: chopper2k22 on September 01, 2008, 01:15:25 PM
Iv got some pictures somewhere but cant find them, so ill have a go at explaining how i did it.

The white conector ring where it plugs in pick the live terminal, i then cut away the plastic and crimped on a spade connector, sheilded it from the other pins and then bent the spade connector so that it makes a contact with the metal ring on the boss. Then use the wire in the middle to earth the horn button out.

hope that helps
Title: Momo boss - how to get horn working!?
Post by: lockwood77 on September 01, 2008, 01:29:46 PM
Hmm, I think I get that, will have to look at some pics of mine (or take the wheel off!)
Title: Momo boss - how to get horn working!?
Post by: probedb on September 01, 2008, 08:25:45 PM
I have a Sparco boss (I think) and took the wheel and cover off recently. The connector on the car (presume the stock connector) has 3 prongs and the top one is the one you need, then if your horn push has 2 connectors just connect one of them to this wire then earth the other on the boss itself.

At least that\'s how mine is setup. Hope that helps a bit :)
Title: Momo boss - how to get horn working!?
Post by: lockwood77 on September 02, 2008, 10:10:28 AM
Hmm, can\'t quite picture that on mine - the bit with the prongs has to be removed to fit the Momo boss (it has the three-pin connector sticking out toward the driver which gets in the way). The problem is making that contact in the first place once the prong carrier (!) has been removed.
Title: Momo boss - how to get horn working!?
Post by: probedb on September 02, 2008, 12:51:44 PM
Mine uses a small spade connector (the female part) with just a wire running from it.
Title: Momo boss - how to get horn working!?
Post by: lockwood77 on September 02, 2008, 12:57:06 PM
Right, sounds like chopper\'s then - will have to take mine off (again) and have a play.
Title: Momo boss - how to get horn working!?
Post by: Nik da Greek on September 02, 2008, 04:53:01 PM
I guess if you have a man enough drill you could just knock a big hole through the bottom of the boss and use the original plastic scotchblock connector? That\'s basically how my Jap-market boss is, it doesn\'t have the brass ring like the Momo boss, just a big hole for the connector block!
Title: Momo boss - how to get horn working!?
Post by: batman on September 07, 2008, 08:39:21 PM
the white wire coming from the dash is the horns positive that connects to the horn button then just run a small tail lead to the steering wheel bolts it will earth through the rack and beep beep
Title: Momo boss - how to get horn working!?
Post by: najiru on September 13, 2008, 03:20:41 PM
Right then this is how I did it...
 
This is the momo boss I used with the large brass contact ring on it.
 
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000965.jpg)
 
First off set wheels straight and took off the old wheel, then removed the 3 screws in the bottom of the plastic column cowling and took the cowling off and was left with this.
 
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000968.jpg)
 
Although the connector on the white ring has three connectors if you look at the old wheel only the one is used, well on mine anyway, and this one is the horn. Its the one on the furthest right in the pic above. The splined shaft of the steering column is already earthed and this connects to the horn push in the momo wheel through the boss, wheel and then the metal ring around the switch itself, see pic below.
 
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000966.jpg)
 
Now take off the white ring and trim away the plastic connector to leave just the three spades, bend the spades over to give the required clearance and add a spade crimp connector to the furthest right to contact with the brass ring of the boss. I bent it so that there is a bit of pressure there to ensure a good contact. As the white ring will rotate with the boss due to locating on the purple plastic piece, this contact does not slide so wont disconnect/wear. Check the contact is good by earthing the spade to the splined shaft using some spare wire. I did this and got nothing at first. I had to give the sliding contacts on the white ring a good clean and bend them out a bit more before they would work.
 
 
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000969.jpg)
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000978.jpg)
 
With the boss on you can see the contact looks good as said before this contact wont slide round the brass ring as the boss, white ring and purple plastic all rotate together.
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000979.jpg)
 
 
Now stick the boss back on, lining it up with the prongs on the purple plastic piece and making it straight for the wheel. Put the central nut back on then test the connections are good by touching the spaded connection on the boss to the boss itself. This should sound the horn. If it works put the plastic cowling back and bolt the new wheel on, connect the horn button and you should be good to go!
 
(http://i277.photobucket.com/albums/kk41/najiru/fitting%20s-wheel/P1000981.jpg)
 
:driving Beep Beep, out of my way commoners....
 
HTH
 
Neil
Title: Momo boss - how to get horn working!?
Post by: Nik da Greek on September 14, 2008, 10:32:25 AM
That\'s well clever! I\'ve gotta be honest, when I bought a Momo boss I looked at it and thought "there\'s no way I can get that to work", sent it back and bought a ridiculously expesnive Jap one instead. Obviously it is possible with a bit of ingenuity, well sussed out! :Thumbs-up
Title: Momo boss - how to get horn working!?
Post by: lockwood77 on September 14, 2008, 02:30:58 PM
That\'s a superb write-up Neil, many thanks! :D
Title: Momo boss - how to get horn working!?
Post by: najiru on September 14, 2008, 02:55:22 PM
No probs, I figured this is a common problem as if you get a momo wheel with FD boss this seems to be what you get.
Title: Momo boss - how to get horn working!?
Post by: chopper2k22 on September 14, 2008, 03:40:09 PM
Thats the way i did it too, but still cant find pictures :(