I have a s2000 with the factory alarm and recently added a proximity sensor. my car was wired for a hood-switch and everything but the actuator was present so i connected the signal from the proximity sensor to the hood-switch wiring and added power and a ground. it seemed to be an easy install and the alarm was working exactly how it was supposed to.

i autocrossed a week from yesterday and had the proximity sensor unplugged to avoid false alarms between autocross runs. on my way home i reconnected the proximity sensor while the car was running. About 10 minutes down the road the horn started honking sporadically and the nearby drivers were NOT amused. i chalked this up to plugging in the sensor while the car was running and maybe tripping out the alarm, but this morning it started happening again. i don't see what i could have done to provoke the alarm this time so i'm a little confused.

if the alarm isn't activated while the car is running.....how could it be sending a signal for the horn to sound?

any ideas would be greatly appreciated!

 

No idea but it did make me laugh. Oh well, maybe the bump will get a response from someone helpful.

 

it is a little funny, but i have been rolling in Valet mode until i get it resolved and i don't like to do that.

the horn is very random and the times it has gone off hasn't been the best places to say the least.

 

I checked w/ my installer and we came up w/ a scenario that may be happening. First, the Honda factory alarm usually does not come w/ the availablity to be wired for a hood pin, which means you probably got the OEM security add-on upgrade which is an alarm that adds on to your factory key fobs and operates like an alarm. ( maybe you knew all this, but just to clarify the situation) If you wired your proxy to be powered all the time then that is the first indicator that it could trip the alarm at anytime. the second thing is if your alarm is triggering while driving then the alarm does not know your car ignition is on, leading to the yellow ignition wire on the alarm brain being disconnected from the ignition harness. One way to check is to see if you can arm your alarm while the car is running. If you can, check the yellow wire. Perhaps during autocross you snaged it w/ your foot and pulled it out, or due to usually not so great installations on subcontracted dealership work the connnector for the Yellow wire actually came undone from the ignition harness. Hope this helps and gives you an area to check, let me know if it was the problem. Also, we have another tip for the wiring of your proximity sensor so it will not be active while you are driving, I'll let you know after I hear back from you.

 

i appreciate the feedback ^


i have since taken power away from the OEM alarm to clear it start fresh. i reprogrammed the remote and then conected the proximity sensor after putting the key in the off position and the alarm not activated. i have been driving a few days now and there haven't been any random honking. it happened at random before though so i'm not ready to say it is fixed yet.

regarding the comments above. the factory OEM alarm came wired for a hood switch but there was no hood switch actuator installed. this is similar to buying an older civic that doesn't come with rear speakers...even though the wiring is in place for them. the proximity sensor is wired to have constant power, but it sends the alarm signal through the wiring for a hood actuator which was already wired to the OEM alarm under the seat. the OEM alarm shouldn't have the ability to actuate while driving because i didn't change the way it receives power. i also tried to activate the alarm with the remotes while driving to be sure and luckily it was unresponsive.

i will give it a few more days and see what happens.

thanks for the input!

 

stillll honking. it actually has started honking more the last few days. i am trying different settings of the factory alarm now to see if that has any impact on the problem. with the factory alarm set to "auto lock" it makes the horn honk and the doors continuously lock while driving....yeah i'm laughing too. i have the alarm set to "manual" now so we'll see how long i can go without honking.

 

Not sure what prox sensor you used?

In any case it should have 3 or four wires: ground, power, warning and alarm.

If the prox is powered all the time it is likely always tripping when driving and causing the OEM alarm to honk the horn when driving. The factory alarm may have a feature that senses if the hood is not properly latched when driving thus honking the horn.

You can fix this by ensuring the prox senor only has power when the ignition is off. Easy way to do this with aftermarket alarms is to use the "ground when armed" output to provide the ground to the prox sensor. In your case you will probably need to use a very low current relay on the power lead to the prox that is open when the ignition is on and a closed circuit when the ignition is off.

Unless of course you can find a lead off of the OEM alarm that provides either a ground or 12V signal when the alarm is armed (and again disappears when the alarm is disarmed).

 

Does the factory alarm have a Valet mode and is it in that mode? If so, maybe the factory alarm treats the hood just like the trunk (many auto alarms do) and thinks the Valet parker is breaking into the trunk.

You could test the theory by disconnecting the prox trip wire, starting the car, then ground the hood input to the alarm. If the horn honks, you know it's tripping because of the hood input and you'll have to figure out how to get it out of Valet mode.

 

well i'm back in valet mode (otherwise honking at random) and have ignored this problem long enough.

the ultimate goal here is to only give the proximity alarm the ability to send a signal when the car is off and OEM alarm is armed. the alarm does exactly what it is supposed to do when the car is off and i'm sure the alarm having power 24/7 is the source of my problem. whether a relay is the easiest way to accomplish this or tapping into a ground or power on the factory alarm...are there any instructions out there for doing this?

thank you for the comments above, but i want to ensure i have specific instructions before messing with the alarm again. i have exhuasted the search for adding the proximity alarm and it looks like i'm the only one with this problem.....