Horn slowly fading out sounding weird

[MSUSaul]

My horn is not sounding like it should. Anyone have this issue? It's going out. : (

[imtheneal]

My 02 X5 has about 230,000 miles on it and the horn is going... anyone have a part number for a replacement horn?

[Moments]

Picking up the horn thread here, from the mists of time...

My Diesel Sport 2005 horn started to sound underpowered, then moved into a phase of sounding like it was being immersed in water, and finally packed in yesterday.

Generally speaking, I don't use the horn very much, but with occasional trips to London the opportunities tend to rise exponentially due to sharing roads with folk who seemingly occupy all of the stages of oblivion when at the wheel. Back to the point though:

1) The relay could be heard to click. The relay is above the glove box fuse panel and I first started with this. Six screws to remove the glove box, four torq screws to drop the fuse panel. The relay was fine - I swapped it with the identical rear window heater relay from the back of the car (in the middle of the three on the right hand side as you look in) and no change in symptoms. I tested the horn relay electrically and it was doing what it should in connecting the two outputs.

2) The horns can be removed without removing bumper or wheel arch liner, on my car anyway. You can feel for the electrical connectors which are at the top, pinch the top middle of each connector which faces the front of the car and you'll feel the connectors release. Drop them free, there are other electrics in the loom so they aren't going anywhere.
Use a 13mm deep socket, with universal joint extension to a ratchet wrench and free the single retaining nut. This bit just needs some care to not drop anything. Then manoeuvre the assembly out past all potential obstructions.

3) I electrically tested the connectors by careful use of a meter and a pin inserted into the plug block. Brown ground, purple hot when horn pressed. No problem.

4) On the horns themselves, the pins in the connector blocks weren't in great shape: one pin on each was visibly corroded. My fix was to get some 1500 grit wet/dry paper, roll up a 3/8 in strip to form a small tube and drop on the pin to be cleaned. With some tweezers that pinch at the very end, grab the abrasive paper and pull up with the tweezers pinched. Rotate and repeat for each pin.

Re-assembled now, I just put everything back and connected. Again, careful not to drop anything, it's just a bit of patience here, and the horns both work normally again.