Horn Wiring

timbo · #1 24th October 2009, 16:57

Hi all
I was using an original BMW steering wheel (air bag replaced with foam) with centre push for the horn, mainly because I couldn't fit the BMW slip ring to my nice Momo steering wheel.
I've decided to put the Momo steering wheel on, and use a spare push button space on the dash for the horn.
I've been using the Savage switches/buttons, which are wired as follows:
1. Power 12v positive
2. Source
3. Normally closed (not used)
A. LED (+) Power
B. LED (-) Ground
Then you put a link between pin 2 and pin A so the LED lights up when you switch it on.
Well because the horn switch is just connecting from the relay (ground output) to ground/chassis, I connected up pin 1 to the horn relay (was originally going to steering wheel) and connected pin 2 to earth, which works fine.
I originally tried pin 1 to the wire from the horn relay, linked pin 2 and pin A, and pin B to earth but the horn didn't work at all then.
So the led doesn't light up (I want the outer one to come on when the side lights come on, and the central one to come on when you press the horn). But I can't figure out how to do it...maybe I'm just being a bit dozy today!
Any ideas gratefully received!
Thanks
Tim

limpabit · #2 25th October 2009, 04:44

Try this Tim.

Pin 1 - connect this to earth.

Connect pins 2 & b together to horn relay wire.

Connect pin A to a +ve 12v source. I'm assuming the led's are 12v led's to get them working!

Rich · #3 25th October 2009, 18:25

How about wiring the LED for the switch to the lights? So when driving at night the horn switch will glow a little. Might need add a resistor so its not too bright.

To get the LED to light when the button is pressed you'll either need to take power from the relay that goes to the horn. Alternatively you can wire a second relay by the switch to turn the earth loop into power.

edit: Tim's suggestion is probably the best, seems like the cleanest way of getting it working.

timbo · #4 28th October 2009, 23:59

Thanks guys, will let you know results. I have to take the seats out to access the switches (not being a contortionist by trade) so will try possible solutions soon...