Horn has a mind of its own

[jkrantz773]

Hello -

my horn seems to have a mind of its own - for the last month or so - it never fails - about 2am, my horn on my 2000 Silverado sticks on (truck is turned off and I'm sound asleep) - it will honk straight for several minutes - most of the time it just turns off on its own -

last night when this happenend, I found if I put pressure on the brake, the horn stops - let off the brake and it goes back on - this seems to be the only thing that will make it stop - however, it will not stay off tell it feels like it wants to -

 

To get this to stop - I've tried turning the truck off/on - messing with the keyless remote - pounding on the horn -

 

It seems - this may of all started when my battery went bad - the post fell off leaving me sitting in a parking lot -

 

I changed batteries and everything else has been fine except this dang horn issue (I don't know if the battery issue had anything to do with it -

 

any suggestions are welcome!

thanks!

jon

[GM-Tech]

Not sure what stepping on the brake has to do with it, unless you're pressing it really, really hard and that causes flex somewhere that moves a wire.

 

The horn relay is activated by the body control module OR the contacts in the horn pad (air bag). What I would do is pull the air bag while the problem is occuring and see if that stops it. Are the horn buttons really sensitive? If you just touch them under normal conditions, does that sound the horn? If so, I would suspect the air bag even more. Temperature changes can cause the button contacts to make contact if they're really close. This usually happens at night when things cool down and contract.

 

Couple other things you can do is remove (or cut) the wire from the BCM to the horn relay. Give it a couple days and see if the problem occurs. If it does, something is telling the BCM to sound the horn or it's a bad BCM. If you still get the unwanted activation, you can rule out the BCM. I think a BCM related problem is highly unlikely.

 

After doing the BCM test, put that back together and remove the air bag and do the same "wait and see". If it is a horn button, you have to replace the whole air bag and it ain't cheap.

[GM-Tech]

Having difficulty figuring out how to reply? Please delete those "empty" posts. Thanks.

 

Taken care of- 99silveradoz71

[rocknrobby]

Not sure what stepping on the brake has to do with it, unless you're pressing it really, really hard and that causes flex somewhere that moves a wire.

 

The horn relay is activated by the body control module OR the contacts in the horn pad (air bag). What I would do is pull the air bag while the problem is occuring and see if that stops it. Are the horn buttons really sensitive? If you just touch them under normal conditions, does that sound the horn? If so, I would suspect the air bag even more. Temperature changes can cause the button contacts to make contact if they're really close. This usually happens at night when things cool down and contract.

 

Couple other things you can do is remove (or cut) the wire from the BCM to the horn relay. Give it a couple days and see if the problem occurs. If it does, something is telling the BCM to sound the horn or it's a bad BCM. If you still get the unwanted activation, you can rule out the BCM. I think a BCM related problem is highly unlikely.

 

After doing the BCM test, put that back together and remove the air bag and do the same "wait and see". If it is a horn button, you have to replace the whole air bag and it ain't cheap.

 

My horn on my 2000 GMC Serria 1/2 ton is exhibiting the same problem this gentleman's horn is. About (2) months ago my horn starting spontaneuosly beeping one night so I pulled the positive battery cable off as a temporary solution. In the morning, I reattached the battery and the problem never came back.....until tonight. I pulled the horn fuse tonight to fix the problem. My horn contact on my steering wheel is not having any problems and sin't overly sensitive so could I have a different problem causing my spontaneous horn? Please advise. Thanks.

[staruser]

I had the same problem until I moved. I found that when I returned to my old neighborhood for an over night stay, my horn would beep. I noticed one night that my horn would start going off right after another truck drove by. The next day, I talked to the guy with the truck and he said that he sets his alarm every night when he gets home. I tried my remote alarm and his truck's alarm system would turn on or off. His remote was activating my alarm. It was also the same with my electric garage door. Another neighbor would use her remote for her garage door and my door would open every morning.