Mtech 2 horn repair

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jvshf
E30 Zone Newbie
E30 Zone Newbie
Posts: 1
Joined: Sat Nov 28, 2015 11:00 pm

Fri Jan 28, 2022 12:35 pm

Hey boys and girls,

My mtech2 wheel used to beep just fine but a few years ago I accidentally hit my wheel with a pretty solid elbow when trying to get something out.

The horn immediately started firing and didn't stop until I turned the car off.

I'm just trying to figure out if I can get it working again and here's what I've already troubleshot:

- firstly the wiring behind the horn looks fine... Brown wires to brown wires and black to black.

- no visible damage on wheel/horn mechanism

- tested horn with m tech 1 wheel, works fine

- based on m tech 1 test, I would assume fuse and relay is fine. Fuse is definitely good, but I was struggling to work out how to independly check the relay beyond measuring its resistance. But I think it's fine if it works with a different wheel, surely.

- there appears to be a spacer behind the steering nut, if I remove this and put the wheel on and press firmly on the outer rim of the wheel, the M tech 2 horn will beep (without me pushing the horn. Only the outer where you put your hands)

- shorting out the steering column and the brass spring loaded pin with no wheel attached (obviously) makes the horn beep


I am wondering/hoping that the spring loaded brass pin (I'm NOT referring to the brass locking pin at 12 o'clock) has worn away to the point where it no longer makes contact with the rear face of the wheel? Potentially the M tech 1 and m tech 2 wheels have different depths on the indide/back of the wheel? But I can't find anywhere that has this part in stock for a reasonable price.

Any help or tests I could do would be greatly appreciated!

Thanks so much! 8)
BristolE30
E30 Zone Regular
E30 Zone Regular
Posts: 532
Joined: Thu May 16, 2019 7:43 pm
Location: Bristol

Tue Feb 15, 2022 11:47 pm

I think you would find that if the brass pin had worn away you would not get any horn at all. This happened to a friend.

It sounds like the circuit is grounding (completing) somehow. I’d be looking at the tabs behind each button and checking they are not jammed on. They just pop off
BMW E30 316 ‘87
BMW E30 325i ‘88 :bmw:
Bristol, UK
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