MGTF horn/alarm not making noise.

Hi all.

Can any one point me in the rite direction.

Horn not working 53 reg/2003 1.8, but making clicking noise under passenger side dash. The horn is a wired into a 40 amp relay under the bonnet drivers side but it's got no serial number on. I tried to get advise from Rimmer bros and ordered one that could have worked but no dice. Is it possible the horn itself is broken any ideas would be great as we keep getting bullied by other vehicles.

Thanks
Dan

I'd start with the simple and obvious.

Disconnect the wire from the horn under the front hood; it unplugs easily. Check the wiring for 12v when the button is pressed, either with a meter or a 12v light bulb (every car owner needs one or the other of these). Check the horn itself by applying 12v to it while it is disconnected.

If you have a Pektron (round keyfob) system, the horn relay is on the body control unit (BCU) circuit board. It is possible to replace it yourself but most people would send it to Technozen for repair.

I'm not sure where the fuse is.

You say that horn is wired to 40 amps relay under the bonnet. If that is true, that means some rewiring was done on your car.
If you have square two button fob you have Lucas alarm system and horn relay is within MFU unit behined fusebox under steering wheel.
If you have oval fob you have as said - Pektron system and horn relay is within BCU unit.

As above, there is no relay under the bonnet in the O/E configuration.

Does the relay click when you press the steering wheels horn buttons?