Electrical Problem: Lost horn and key/headlight on warning chimes

[Mustang5L5]

At 30K miles i had my first gremlin. I lost the horn as well as the key in/headlight on warning chimes.

I did notice that right before I lost the horn it sounded weak and broken. Afterwards nothing at all. Next day i noticed the chimes were not working.

Car is still under warranty but i don't want to lose time/money in bringing it in if i can solve it in an hour or so of work.

First things first, i don't have a manual so where is the fuse for the horn?

Secondly, what would these things have in common to cause them to go out at the same time??

If anyone has any wiring diagrams for a 2003 that would help.

 

[n0v8or]

I have the '03 manuals, and I don't see anything common that would kill both the horn and headlamp warning chime. Do you have an aftermarket alarm installed?

The horn fuse is a 20A mini-fuse located in the fuse/relay box near the battery. Open the hood, Standing by the front left tire, push in the tab nearest the engine and lift the cover. The first 4 fuses (top to bottom) in the left column should be 20A - 20A - 30A - 20A. The second one from the top is the horn fuse.

 

[Mustang5L5]

Nope, my car is pretty much stock. No alarms.

It went out while driving during a rainstorm. I just happened to notice the chimes not working as well.

Horn switch "clicks" like normal and when i hit the lock button twice the horn no longer beeps but the parking lamps flash

 

[Mustang5L5]

You gott be kidding me.

Went outside to check the fuse and now the horn and warning chimes work fine! What gives!

Something must be shorting. Anyone know what these would share to cause such a thing?

 

[n0v8or]

The weak horn before it died suggests a bad horn relay.
There is a plastic relay box right behind the fuse box under the dash. It has 4 relays in it. The 2 relays farthest from the fuse box (therefore closest to the engine) are the horn relay and trunk release relay. You could try swapping them (I think they are identical) and see if the problem moves. Sometimes just removing and re-seating a relay fixes it.

 

[Mike97gt]

i just noticed this thread. keep us posted if it comes back. just bump it to the top with the details.