electrical and ignition Please explain the Horn Circuit to me?

[josh72ooh2]

Hello Gang,

 

I replaced my turn signal switch (the old one was shorting out my electical system causing blown fuses and other issues).

I also replaced the wire and contact button that connects the horn button to the contact ring on the steering column (old wire was brittle and broke). 

 

My horn was working and no longer works. 

 

Can somebody explain if it has something to do with any of the wiring related to the turn signal switch?

 

And,  where would I typically find the horn relay on a 1972 2002? 

 

I'm guessing the turn signal switch or the relay is the culprit. 

 

-Josh

[FunkyLaneO]

It is a pretty simple circuit, check to make sure you have ground at the steering wheel and try touching a ground to the horn ring surface to bypass the horn switch. if it honks then the horn switch needs to be looked at.  I believe the wire is purple/yellow (on later cars maybe yours too) it goes through a couple connectors before it gets to the relay, you may want to trace the wire and check those.

 

The relay should be up at the front drivers side in the engine compartment, find the one with the purple/yellow wire and check that one, you can put your hand on it and have somebody push the horn and feel for a click, if it clicks then it is probably good and I would take a look at the horn itself.

[Buckeye]

Also read last thread on this link.

http://www.bmw2002faq.com/topic/120462-intermintent-horn-honking/

[PaulTWinterton]

If your horn works by touching the positive wire to the steering column the spring-loaded contact on the back of the steering wheel may not be touching the ring when the wheel is bolted on. It can be very close, but still not contact.

Two things that can make that happen. Spring is weak, or the contact ring is not properly seated in the shroud.

[josh72ooh2]

It is a brown with a yellow stripe wire.  It goes straight into the harness and there does not seem to be a relay under the steering column area aside from the washer relay (i think) and the turn signal relay. 

I tried grounding it out and I get nothing... i think it is the relay... but where oh where is the relay?

it is a 12 fuse car made in '71. 

[Mike87]

The horn relay should be on the drivers side fender up by the battery. Round aluminum cannister if it is original IIRC.

[josh72ooh2]

Ok.  I found it.  I had replaced it with a more modern relay when I converted my headlights to the relay system... and totally forgot!  Douph! 

I have a series of 3 relays mounted nicely in my engine compartment and I thought they were all for my headlights. It turns out that one of the plugs came off the terminal.  All is well now.  beep beep.