Just bought a pair from ebay which came with a short pipe/tube and two wires (red & black)…I need to fit them to an R Series Topliner (Gaffer doesn’t mind as long as they go under the cab and not on the roof). So, can anyone offer me some (constructive) advice and fitting instructions please as I’ve nothing on paper and I’ve never attempted this before - By the way, are these Train Horns ‘legal’ in the eyes of the Vosa Gestapo chappies?
Thanks in advance…
easy to fit, on a scania the best place is under the back of the cab on the passenger side floor {under the locker}, theres a blank on the air tanks to pipe them to, then for easyness connect the two electrical wires to your standard horn in place of the origanol wires then it works from the steering wheel, i,ve had no probs getting stopped on the road by vosa but it wont pass mot as 2 tone horns arent allowed so its a quick 5 minute swap of the wires to get the scania horn reconnected for mot
btw, just make sure you run the airpipe all the way to the front of the cab then along the inside of the chassis rail and to the tanks otherwise you wont be able to tilt the cab 
if you have all the gear its an hour job max
Thanks for your reply Chaversdad - much appreciated 
As far as I’m aware, multi tone horns are not legal for highway use. Personally, I’d wire them on a seperate switch. Then yr standard horn is still effective and legal. It only takes 1 over zealous vosa inspector and a pg9 and yr boss won’t be pleased.
Thanks Mr Vain - beginning to wish I’d never bought them now!
Are they actual train horns or just eBay versions, there is a big difference in sound and price.
Real ones sound like this
youtube.com/watch?v=BSifXDK_S_0
The ones on eBay are ok but not a patch on the real thing
Express Pete:
Thanks Mr Vain - beginning to wish I’d never bought them now!
Ways and means mate. Its not a major job really. Better safe than sorry.
just to add, if you want loud but not 2 tone to keep it legal, then just put the wires the wrong way round.
wire it like i said to the scania horn but instead of red to red go red to black and the same for the other wire, all this does is makes both horns blow at the same time instead of the 2 tone you would have had, still loud but legal as well
nickyboy:
Are they actual train horns or just eBay versions, there is a big difference in sound and price.Real ones sound like this
youtube.com/watch?v=BSifXDK_S_0
The ones on eBay are ok but not a patch on the real thing
I would so love a set of Nathans, alas got no room for them on the car 
I do have these fitted to my MG though…
Thanks fellas much appreciated - think I’ll take your route Chaverslad (reverse the wires)