New member to this site. I have a 2004 MDX 38K mileage. The horn does not work.
Here is what I did so far: Checked the 7.5 amp fuse in the drivers side aux fuse box.(tough to get too!) Fuse is good. Removed the horn relay and check for 12 VDC going to coil when horn button is pressed on steering wheel. 0 vdc. Had 12 + VDC at the horn relay contactors. Jumped out and horn contactors and it did blow. Just to double check I did swap the horn relay with the light relay and horn did not work.

Moved to the steering column and there where two excess covers that you could see the brass contactors make when the horn on the steering column is pressed.

I am assuming that the problem is in the steering wheel area but not sure what is the next procedure. Also about a year ago there was an issue with the remote radio buttons on the steering wheel and it was fixed at the dealer ship under warranty, and yes the horn has worked since then.

 

horn and lightflasher relays are not the same

 

I said light relay, not light flasher. The relay next to it was the auto wiper relay, I believe. That is the one I used. Sorry for the mistake. Same pin configuation. The only difference was the # on the relay. Would that be the contact amp rating? The problem is there is not a ground coming from the steering col. I am going to try and get the repairs done by the dealer under warranty.