240Z horn points adjustment

[GIchiro]

SO I have 1 horn working now (adjustment screw) but the second horn would not work. I took it apart and it has a set of points in it. So I adjusted the screw all the way in but cannot get the points to separate. Are the points supposed to have some separation?

[Captain Obvious]

I haven't been inside one of those, but I bet there should be no gap and those contacts should be closed. I'm assuming those contacts will open and close rapidly when power is applied to the horn and the oscillation of those contacts is what makes it BEEP. Or at least that's how it's supposed to work.

The pressure on the contacts is what is controlled by the pitch adjustment screw and determines how hard those contacts are pressed together. That pressure will change the frequency at which they open and close, and that changes the pitch of the horn.

If you have an Ohmmeter... What resistance do you get across the horn? And how about the other one (that works).

[Captain Obvious]

And just because those contacts LOOK closed, are you sure you're getting electrical contact across them? Maybe drag a piece or paper between them to clean up the contacts a little?

[GIchiro]

Good idea Capt. I will do the contact cleanup and test outside of car

[Captain Obvious]

Good luck, and I hope its that simple. 

I'm thinking there should be a pretty low resistance measured across the two horn wires coming out of the assy. I bet the working horn is a pretty low, and the non-working one is open circuit for some reason. Could be those contacts, or it could be elsewhere.

[SteveJ]

The contacts should be closed. 

 

[GIchiro]

That is awesome. Thank you. GI

[Namerow]

On 4/17/2018 at 9:21 PM, GIchiro said:

Are the points supposed to have some separation?

When you start playing with the adjustment screw, I think you're going to find that the adjustment window for optimum sound/volume is pretty narrow.  I suggest that you loosen the screw to 75% of its full travel to start.  Then, with power applied to the horn, start tightening the screw.  Take the horn past its point of max. volume, then back the screw out to re-find that point.