Horns won't stop blaring)))!!!! Please Help

[NZboundNSX]

Hey guys. I’ve got a problem, and this one just occurred @ 1:45AM in the morning with several loud urgent knocks at my front door. Somehow my 91 NSX decided on its own freewill to blow its 2 front horns ..and this apparently was going on for nearly an hour before my poor neighbors decided it was time to wake me up. As the horns were blaring I turned the car on but that did not stop them. My next effort was to unplug them.. but, umm it’s not so easy to get 2 ears and your hands into that area when it’s dark and raining outside. So I decided to unplug the battery. I am positive this sound was coming from the horns (they were as hot as fire).

Here are the details. I have no mods on the car, it's completely factory, including its factory alarm. The alarm horn behind the drivers headlight was not screaming. The car did start during this nightmare, but that did not turn the horns off. New Battery 4 months ago. The car has not been driven for 2 days. It had been raining hard and soft all day. Why is the NSX not in my garage and outside in the rain? I am building (part by part) a new 2006 Diesel Mercedes Smart car in my garage. The project is almost complete, but taking up my entire garage, so the NSX lives outside for a while.

What on earth could have caused both my horns to go off and not turn off? Could a relay have failed? What relay controls the horns?

Ahh it’s currently 2:45AM, i’m going to hit the sack. Please help me out here.
Thanks zzZ

 

[D'Ecosse]

There are three horns in the NSX - two in the front bumper 'grille' area and the third security horn which is located in the left side of the front compartment. All three horns are wired in parallel so if one comes on, all three should come on. I can only imagine the reason for the third one located inside the compartment is that the main two are readily accessible from oustide the vehicle and it would be easy for potential thieves to

It sounds like you had an alarm condition - the lights normally flash but that stops after 2 minutes. (Not 100% sure but think the horn stays on).
Try setting & resetting the OEM alarm with the drivers door key - have the hood closed while you do this. To get into a pre-condition where you can actually do this, remove the horn relay, reconnect the battery & close the hood. Then with your key in the door-lock, un-lock, re-lock & un-lock again. Open hood & re-insert relay & see what happens.

Note that the door position switches are notorious for failure on the older cars and covered by a TSB - it's possible that this is what triggered your alarm (although may also have been real attempt at theft)

http://www.nsxprime.com/FAQ/Reference/tsb/93-007.htm

Click on images for full-size versions

 

[LJSB]

I read it as if his horns were sounding steady not doing the on/off report that the alarm system does.
Also, I assumed he used the remote or the key in the door to get inside to pull the hood release. I would think if it was the switch for the alarm one pf these actions might have reset it.
To me ,I think it most likely a bad relay or bad horn switch.
Perhaps the rain and resulting moisture had something to do with this?

Was a rain sensor a factory option?:biggrin:

 

[NZboundNSX]

D’Ecosse, thank you for your time and the detailed reply. Your info has put me in the area of the problem, but the problem has not been solved yet.

Pbassjo is correct. I did all of the following that his post mentioned.

I feel strongly that the problem was not due to the alarm. Thinking the alarm was triggered I did try to reset it with the door switch & key, that did not work. Also, in the past when my alarm has gone off the car would not start. In the case of the 2 screaming front horns, the car did start, but that did not turn them off. I disconnected the battery.

I still can not seem to figure out which relay to check?

 

[D'Ecosse]

I still can not seem to figure out which relay to check?

Here you go .......

 

[NZboundNSX]

HUGE Thanks D'Ecosse!!!

I've been looking for a diagram that specifies my relay's since I bought my car. I am sure the problem can be found now. I will update as soon as it's fixed.

Say's to self ..man this site is Prime! :biggrin:

 

[D'Ecosse]

Maybe you weren't aware of the '91 Shop Manual here on 'Prime?

Pretty good for 91-94's with minor changes on those years. Will cover most of the other years too, with some obvious differences.

 

[LJSB]

Is this guy D'Ecosse good or what? :wink: