The other day, my horn pooped out, so I went to the junkyard and got three for six bucks, one from a 240D (the other was inaccessible) and two from a Beemer.

The Beemer horns just moaned pitifully, so I soaked them overnight in WD-40 and then, with them moaning pitifully, turned the small adjustment screw. This with only minor fiddling, produced a respectable sound from each horn, one high and another lower.

The 240 D horn was a round drumshaped thing that did not require any fiddling at all. The Beemer horns were made by FIAMM in Italy and had a bell

My question is why doesn't it seem to make any difference which wire is connected to Ground and which to 12V?

My grandfather used to tell me that a flashlight would not work with the batteries in backwards because it was DC. But the horns are also DC.

I am sure there is a simple answer. I'm afraid my physics class did not get into "hardware issues", so please forgive me if this is a truly stupid question.

Will using a relay make the horns any louder? Are the numbers on relays (87, 87a, 30, 86) some sort of standardized code, by the way?

And Danke, Gracias, Merci, Thanks, Shi-shi

__________________
Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)

Thanks!

The leads for the beemer horns are brown for the ground and purple for the hot lead. There is a right and left side to the socket on the horn wires where it plugs into the horn. I will make sure I install it as the previous horn was wired.

I assumed that the cause of the sound was a vibration caused by an electromagnetic circuit.

I asked about the relay because some cars have horn relays and others don't. Air horns always do, electrical horns mostly don't, but some do.

However, I have fiddled with batteries and bulbs quite a bit, and no matter how good the connection is, the bulb will only light if the + goes to the button on the bottom of the bulb and the - to side of the bulb. Reverse the leads and nothing happens, even if you solder them on.

Is there a difference between light and magnetism, perhaps?

Electrons can produce magnetism whether the flow from L to R or R to L, but light only from R to L? That doesn't sound right.

__________________
Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)

I suppose that flashlight bulbs, your standard Ray-O-Vac or Eveready or Red Dragon Brand Finestkind Made in Hong Kong Torch flashlight bulbs must be polarized then, because the bulbs won't light unless the polarity is correct. I spent hours trying to make this happen once, using solder and ever other way to connect the bulb.

Walkmen, Boomboxes, cassette players MP3 players and digital cameras also will not function unless the polarity is correct


But thanks!

__________________
Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)