Horn fuse keeps blowing

swolk99 · Aug 28, 2016

Hi, I have a 2010 CX-9. Last night I discovered my horn is not working. I checked the fuse and it was bad. I replaced it with another 15A fuse, it it blew right away. Does this mean there is a short somewhere? Could the horn relay be bad?

Might be related, but when we get a really heavy rain or go through the car wash, the alarm/horn will start going off seemingly randomly, like some water got in somewhere. After a while it clears up. But, I havn't washed the vehicle and we haven't got any rain recently. I had seen an issue with CX-9 with moon roofs having issue with drain clog causing water to penetrate BCM. My vehicle doesn't have moon roof so don't think there is an issue there.

Thanks,
Scott

astriuminc · Aug 28, 2016

swolk99 said:
Hi, I have a 2010 CX-9. Last night I discovered my horn is not working. I checked the fuse and it was bad. I replaced it with another 15A fuse, it it blew right away. Does this mean there is a short somewhere? Could the horn relay be bad?

Might be related, but when we get a really heavy rain or go through the car wash, the alarm/horn will start going off seemingly randomly, like some water got in somewhere. After a while it clears up. But, I havn't washed the vehicle and we haven't got any rain recently. I had seen an issue with CX-9 with moon roofs having issue with drain clog causing water to penetrate BCM. My vehicle doesn't have moon roof so don't think there is an issue there.

Thanks,
Scott

Most likely water in the horn unit itself, I believe horns are hiding behind the grill, not sure but when you go thru car wash, they get more wet and go off, maybe try to find the oem horns and disconnect them, then replace fuse and see if the fuse blows? There's two horns. One high tone and one low tone.

swolk99 · Aug 28, 2016

astriuminc said:
Most likely water in the horn unit itself, I believe horns are hiding behind the grill, not sure but when you go thru car wash, they get more wet and go off, maybe try to find the oem horns and disconnect them, then replace fuse and see if the fuse blows? There's two horns. One high tone and one low tone.

You are right! I picked the high horn and disconnected it. When I tried to honk the horn, still no sound but the fuse did not blow. Connected the horn, then when tried to honk the horn, fuse blew.

Two follow-up questions:
1) Does it make sense that the low horn doesn't make a sound when high horn is disconnected?
2) Do I need to just replace the high horn?

Thanks,
Scott

astriuminc · Aug 29, 2016

1) Does it make sense that the low horn doesn't make a sound when high horn is disconnected? yes, I believe they are connected in series

2) Do I need to just replace the high horn? maybe reconnect the high tone and disconnect the low tone ? if fuse blows then high tone is your culprit and replace

Horn fuse keeps blowing

swolk99

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astriuminc

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swolk99

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