nsnell19

The fuse to my horn has blown 3 separate times, and each time I've had it replaced by the dealer (my 8 is still under warranty). Well, last week, my remote keyless entry system suddenly stopped working, so I went into the dealer yesterday (saturday) where they gave me 2 new remotes and reprogrammed them. Everything was working fine until this afternoon my horn blew AGAIN!

The dealer can't seem to find the underlying electrical problem that is causing this short. Am I crazy? Is there an underlying problem or am I really supposed to be replacing my horn fuse every few weeks?

I don't know if this has anything to do with the keyless remotes they just reprogrammed...but the horn honks when I arm it so I'm thinking it is all somehow connected.

Please Help!!

Nubo

To be fair to your dealer, intermittent faults like this can be difficult to track down.

But, repeatedly blowing fuses definitely indicates a problem that needs to be fixed. Blown fuses represent possible short circuits, which are a danger. It's not something that should be ignored.

nsnell19

Thank you! I figured it had something to do with an electrical short somewhere. I've also noticed that the light inside my glove box comes on intermittently. Sometimes it's on, sometimes it's not. There's no pattern....it's completely random. Would this be related to the short? Where could this short circuit be if it's only affective lights and horn? Should it be pretty easy to fix?

I appreciate your input!

SilverStreak

Excellent suggestion CBD. Always best to track when things happen, it took me months to diagnose a poor idle in my wife's Miata (three different things that were all related electrically, each step improved things until I figured it all out).

NSnell, Looking at the electrical schematics (section 13 of the service manual page 62), I don't see any connection between the horn and intermitent glove box light so I don't think the glove box would have anything to do with blowing the fuse. There isn't much to the horn system. Just a horn switch, the horn relay and the horns themselves. The horn switch is in the steering wheel and all it does when you hit the horn is provide a ground to the coils in the horn relay switch (this completes the circuit, energizing the horns). My best guess is to check the battery grounding and the horn relay switch (which appears to be in the main fuse block under the hood). If the horn relay switch is sticking, it could cause a blown fuse. Hope that this helps.

SilverStreak

On page 110 of the electrical section, it shows that the keyless control module actuates the horn but isn't real specific as to how this works. It also could be related as we know that pressing the lock button twice gives us a beep. Of the three, the keyless control module would probably be the last thing to check and the most expensive to replace. I'd check ground (damn near free), replace horn relay (cheap), then keyless control module.

Nubo

Having 2 normally reliable systems fail raises a flag. And they both seen to have the horn in common.

One of the most useful things that can happen is if you find a way to replicate the problem, so that you can say exactly what happened right before the fuse blew.

Seeing as you're not in New York City, I am assuming your usage of the horn is a fairly rare event That makes a possible tie-in with the security system seem more likely.

I would suggest trying to recreate the problem by activating the remote several times. Double-click so you get the horn beep... unlock the car with the remote.... activate with beep.... repeat. Wait a couple of seconds between each action. I'd try it half a dozen or maybe even ten times in a row. If at some point the fuse blows, that may be useful information to help the technician isolate the problem.

I'm with Silver Streak concerning the relay. If there is a connection between the security system and the horn fuse, that would seem to be the point of commonality.

nsnell19

Thank you all so much for your suggestions. My horn is currently out right now, and I'm taking it back to the dealer on Saturday to have them replace the fuse and look into the electrical system. I'm going to print out all of your comments and bring it in with me so that they have some good advice to go off of!

Cool-Blue-Dad, I will start carrying a notebook and write down when something weird electrical goes on.

Nubo, You're right, I live in LA and don't use my horn that much, but I use it a few times a week. When the horn went out on Sunday, I was honking at someone who pulled out in front of me and the horn died in the middle of the honk. It has been about 2 months since the last time the horn blew and this time. Before that, the horn blew a fuse 3 times in 3 weeks.

When my keyless remote/alarm stopped working last week, the horn still worked. And the horn still worked after they replaced the 2 remotes and reprogrammed the system. Then out of the blue, a week later, the horn stops working.

I know electrical problems are frustrating for everyone, but it kills me not to have my horn and to have to take my car to the dealer every Saturday (and they're not that close to where I live).

Thank you again for all of your input! I really appreciate your expertise.

nsnell19

Took my car to the dealer today and they told me to bring it back during the week cuz they're going to call Mazda to try to figure out the short circuit problem. They're gonna get me a rental car, which is really cool of them. In the meantime, I learned how to change the horn fuse so I can fix it myself if it goes out by Thursday.

Thanks to everyone who offered their advice!

Easy_E1

iTrader: (2)

Don't the Tech's know how to read an electrical schematic?
And do a continuity test on the wire harness? Sound's like a simple short to me.
Good god I do it every day.