Hi,
The last few days my horn has been intermittent but always had a healthy sound when it did work. Now, nothing at all. Tonight I had a few minutes and checked the horn fuses which I replaced even though they all looked good. Each time I activated the horn switch I heard the relay switching on. I thought that maybe the relay was bad. I checked the relay and as expected it clicks on when given 12 volts and to my disappointment I did get continuity across the other two posts when the relay coil got 12v. So I am assuming the relay is fine. Tomorrow I plan on going directly to the horn to see if they work when I directly apply 12v. Since the horns sounded good whenever they worked I suspect they are fine but never the less will be checked.
My first question to you experts is what should I look at next if the horn work with 12 volts applied directly to it? Do I simply run a new wire from the relay to the horn if I can't see an obvious problem to the wire? I think that I read somewhere that my car has two horns, is that correct? Last question is where are my horns located.
One more piece of information. Even with the horn fuses removed the relay is still activated when I push the horn switch. Is this simply because the wire from the relay that I suspect goes to the horn(s) goes through the fuse box first??
Thanks very much!

 

Swap the relay with the RH engine fuse box king relay

The engine won't run but gives you a test.

The horn relay has 2 sources of power and 2 fuses . One to blast the horn and one to control the relay .

The contacts inside the relay are probably pitted which will show continuity or a voltage reading but not enough current to run the device ( horn ) , This is common

The 2 horns are located just inboard of both inboard headlights

 

It's going to be corrosion on the spade cconnectors plugged into the horns. Mine did the same thing recently. Wire brush them + electronic contact cleaner or salt/vinegar mix and they will work again.
You'll need to remove front grill inserts to get to them. Each holding on two small screws.

 

Lady P was correct. It was a bad relay. I cleaned the contacts last night and just put the relay back in the car and the horn works fine- until the contacts go bad again

 

Some light bulb grease on the relay pins will work , the heat will spread it around

 

and if you want to get some attention:
I used to replace my weak motorcycle horns with fiamms from MB. When I hit the horn button is would scare me (the one holding the throttle) ! The ones I was trying to scare off would look around for the big car and almost run me over.
Kidding aside, the fiamms really have a piercing, attention getting sound.
wj