I’ve bought an All Ride black twin air horn to install under the cab on a MAN TGX. Can anyone advise me how it’s done and where I can buy the air line and (what) fittings are needed please?
Ta in advance - Pete
I’m assuming that the air horn you’ve bought is the train horn type? Twin tone, 2 solenoid and one air feed?! If so bear in mind these horns are not up to mot standard, therefore will need a completely seperate switch/feed from the original horn.
I’ll also presume the tgx hasn’t got the standard air horns on the side of the cab.
If it did have then fitting would be incredibly simple as there is a switch in the dash to change between air horns and the electric ‘roadrunner’ horn so you could use the electric horns feed as the standard air horns are up to mot standard. You’d just need an air feed.
I don’t mean this in an offensive manor but unless you’re confident in wiring relays, switches etc and know your way around the trucks air system, I wouldn’t attempt it. Let a competent person do it. If you are competent then you’ll easily figure it out.
Topic hijack,sorry.
Is fitting 12v horns to a tgx a pain in the ■■■■. ie dixie horns.
dowahdiddyman:
Topic hijack,sorry.
Is fitting 12v horns to a tgx a pain in the ■■■■. ie dixie horns.
Just take a 12v feed off ONE of the batteries and use a relay so the 24v can switch it on.
mucker85:
dowahdiddyman:
Topic hijack,sorry.
Is fitting 12v horns to a tgx a pain in the ■■■■. ie dixie horns.Just take a 12v feed off ONE of the batteries and use a relay so the 24v can switch it on.
Relays are either 12v or 24v, you can’t feed differing voltages to a relay. Not one i’ve ever come across anyhow. 
I would also never advise taking a feed off one battery to work an appliance. Something like a little dixie horn you’ll get away with but the proper procedure would be to fit a voltage dropper. If you don’t, the appliance will drain one battery.
Rusty Nail:
I’m assuming that the air horn you’ve bought is the train horn type? Twin tone, 2 solenoid and one air feed?! If so bear in mind these horns are not up to mot standard, therefore will need a completely seperate switch/feed from the original horn.
the above is easily worked round, place the horns under the cab or wherever you are putting them, the front airtank on the TGX should have a blanking plate, run the airline from the spare bung in the tank to your horn, theres your air supply, next disconnect the wire from your factory horn and connect these two wires to the solenoid on your train horn, your horn will now operate from the button on the steering wheel, now as said above the two tone operation is an MOT fail so before the due day just swap the wires on the solenoid over and both tones on the horn will now sound together which is not an MOT fail, I,ve fitted these horns on 3 trucks with this method and no issues at all come MOT
chaversdad:
Rusty Nail:
I’m assuming that the air horn you’ve bought is the train horn type? Twin tone, 2 solenoid and one air feed?! If so bear in mind these horns are not up to mot standard, therefore will need a completely seperate switch/feed from the original horn.the above is easily worked round, place the horns under the cab or wherever you are putting them, the front airtank on the TGX should have a blanking plate, run the airline from the spare bung in the tank to your horn, theres your air supply, next disconnect the wire from your factory horn and connect these two wires to the solenoid on your train horn, your horn will now operate from the button on the steering wheel, now as said above the two tone operation is an MOT fail so before the due day just swap the wires on the solenoid over and both tones on the horn will now sound together which is not an MOT fail, I,ve fitted these horns on 3 trucks with this method and no issues at all come MOT
Entirely possible to do it that way, i just can’t be arsed with swapping things around. Plus i have no worries if i do get pulled by vosa for an inspection.
its not exactly a massive load of work swapping 2 wires round once a year
(I don’t ever recall getting a tug where they tested the horn either) 
Rusty Nail:
mucker85:
dowahdiddyman:
Topic hijack,sorry.
Is fitting 12v horns to a tgx a pain in the ■■■■. ie dixie horns.Just take a 12v feed off ONE of the batteries and use a relay so the 24v can switch it on.
Relays are either 12v or 24v, you can’t feed differing voltages to a relay. Not one i’ve ever come across anyhow.
I would also never advise taking a feed off one battery to work an appliance. Something like a little dixie horn you’ll get away with but the proper procedure would be to fit a voltage dropper. If you don’t, the appliance will drain one battery.
You can have 24 v relay switching 12v supply . you can have 12v to pin 30 ,12v feed out to horns from pin 87, 24v from switch to pin 86, and earth pin 85 to chassis.
Only thing you need to worry about is taking an air feed from a protected circuit because if you take it from a primary feed you are breaking the law.Must not be linked into any circuit where the horns operation can have an effect on the braking system.
Link it into the air suspension,air seat or the manifold that feeds the auxiliary tank.These all have isolating valves.This stops the brakes losing pressure if an airbag,air pipe or auxiliary component fails.
Bking:
Only thing you need to worry about is taking an air feed from a protected circuit because if you take it from a primary feed you are breaking the law.Must not be linked into any circuit where the horns operation can have an effect on the braking system.Link it into the air suspension,air seat or the manifold that feeds the auxiliary tank.These all have isolating valves.This stops the brakes losing pressure if an airbag,air pipe or auxiliary component fails.
+1 Don’t overlook this.
Strangely haven’t seen seen system protection tested on MOT for a while, it used to be a common cause of failure.