Phil Robson
Well-Known Member
Many of you may have had the problem where at least one of your car's horns doesn't work. With BOP it's the Low tone, which means the sound is rather feeble for a car with such presence!
It's difficult getting 2nd hand Low horns off the likes of ebay & I don't want to spend £100 on a NOS one if I can repair the existing one (always more satisfying of course). I have tried a newer (part plastic) horn, but it sounds more like my daughter's Fiat 500
I thought I'd have a look inside, so I ground off the rivets:
This is what's inside:
I'm no good at electrics at all, but they seem to be basically a diaphragm with a metal rod inside a coil. When the current passes the electric field forces the rod upwards which in turn operates a switch (contact breaker) that disconnects the current & the diaphragm returns to its normal state, to start the process again a very-many times a second, giving the vibration that is amplified through the 'trumpet'.
There is an adjustment screw which appears to be for tone (it will change the length of time the switch stays closed hence the number of vibrations per second) & a top adjuster that seems to alter the maximum travel of the diaphragm.
Here is the switch (corroded in this case):
I've cleaned the switch up nicely but can't get the horn to work when connected across a battery Surely, it can't be that difficult, but it's beyond me at the moment.
It's difficult getting 2nd hand Low horns off the likes of ebay & I don't want to spend £100 on a NOS one if I can repair the existing one (always more satisfying of course). I have tried a newer (part plastic) horn, but it sounds more like my daughter's Fiat 500
I thought I'd have a look inside, so I ground off the rivets:
This is what's inside:
I'm no good at electrics at all, but they seem to be basically a diaphragm with a metal rod inside a coil. When the current passes the electric field forces the rod upwards which in turn operates a switch (contact breaker) that disconnects the current & the diaphragm returns to its normal state, to start the process again a very-many times a second, giving the vibration that is amplified through the 'trumpet'.
There is an adjustment screw which appears to be for tone (it will change the length of time the switch stays closed hence the number of vibrations per second) & a top adjuster that seems to alter the maximum travel of the diaphragm.
Here is the switch (corroded in this case):
I've cleaned the switch up nicely but can't get the horn to work when connected across a battery Surely, it can't be that difficult, but it's beyond me at the moment.
Last edited: