DeTomaso Mailing List: February 98, Message #147
     



From: 	"Cristiano Rossi" <Rossi@image.dk>

Subject: Horn relocated to wheel - Finally !!!

Date: 	Tue, 3 Feb 1998 15:29:08 +0000



Hi guys,



Finally, I have dismounted my steering wheel so that I can tell those of

you who are interested how I relocated my horn to the steering wheel. 



It is really quite simple. The job basically consists of two different

tasks: One is to give the horn button (that I presume that you already

have) a permanent positive current. The other is to insulate this positive

current, so that it does not make a short cirkuit and make the horn blow

all the time.



First, take off the steering wheel. In the wheel that I have (a Momo

Prototipo), there is naturally the big "mounting hole", and besides it

there is another small hole that is parallel to the "mounting hole". This

small hole has a diameter of about 5 mm., I think. The small hole is

visible from the "backside" of the wheel and also from above, when you take

off the horn button. If you don't have the small hole, you must drill it.

It can not be seen when your horn button is mounted. 



I then made a perfect cirkle of a piece of copper brake-tube and welded it

together. The inside diameter of this ring is about 2,5 cm. This copper

ring has an extension about 5 cm.'s long, also of copper. This extension

goes through the small hole in the wheel. To isolate the extension

electrically from the steering wheel, I put around it a piece of a plastic

fuel line.



The copper ring must now be fit around the large "mounting hole" on the

underside of the wheel. Between the wheel and the copper ring, I glued on a

piece of rubber for isolation. Now you have the copper ring with the

extension mounted on the wheel, but being electrically isolated from the

wheel. 



On the upper end of the copper extension, the part of it that you can see

through the hole where your horn button was, you must fasten a piece of

wire that goes to the centre of the horn button. When you now put on the

horn button again, this button will, when the wheel is mounted, have

electrical connection at one side to the frame, through the "mounting hole"

in the wheel that goes to earth, and at the other side to the isolated

copper ring through the isolated extension.



Finally, you have to give permanent current to the copper ring. The reason

why it has to be a ring is that the wheel is turned all the time when

driving, so a wire connection would not last long. I used a small spring

that was isolated from ground and mounted so that it always touches the

isolated copper ring. Then I took the current from the positive wire of the

existing horn button and connected it to the isolated spring that has now

always positive current.



Now, the spring has positive current permanently, and so does the copper

ring that is always in touch with the spring. The isolated extension that

goes up to the horn button has also always positive current, and this

permanent current goes to the centre of the horn button. 



When you now press the horn, you will make a cirkuit through the spring,

the ring, the extension, the wire, the horn button and the wheel itself to

ground, and therefore, the horn will blow.



The system has now worked for about ten years.



If anybody has further questions, or if I did not explain something good

enough, please don't hesitate to contact me.



Cristiano Rossi

thpnma 02869