glass breakage sensor won't work

A few months ago, I purchased an optional DEI brand glass breakage detector, model number is 506t, which I added to my Excalibut alarm.  I was assured by the online retailer that sold it to me that it would work with my alarm. I even sent an e-mail to Ecalibur directly and they also said this sensor would work.  Well, it doesn't, and I'm not very happy.  But I want it, so I kept it.  After it did not work being plugged directly into my alarm's added plug adapter (one male into box, with 3 female plugs on it for plugging in extra sensors), I wired it directly into the alarm's dome light circuit as an alternate install, just as the instructions stated.  Still won't work.

Maybe I got a defective unit?  Who knows, but it won't work.  I hooked it up exactly as the installation instructions said to.

Anyone familiar with the DEI brand of glass breakage sensor?  They technically call it a "Audio Sensor".  Again, the model number is 506t. 

All of the other features on my alarm are working fine, as is the added proximity sensor, so I know it's not an issue related to the alarm box.  I just wish I knew how to get this glass breakage sensor to work.  If nothing else, I suppose I could order the more expensive Omega AU-80 that Excalibur makes for my alarm.  I'm just worried that if the Directed Electronics one won't work, that the Omega one won't work.

Anyone have any luck with either brand?  How about with the Excalibur alarms?  I used to have an Ungo glass breakage detector and it always worked excellent.  Now I can't get this one to work.  Trouble is, they say that if your alarm does not have a direct plug dedicated to glass breakage sensors, to cut the plug off the end and wire it directly, which I did and still nothing.

Thanks for any advice you might be able to offer.  And I'm open to suggestions of any other brand of glass breakage sensor/detector that you are sure will work with my Omega Excalibur alarm.

How are you testing the unit to see if it works?

Red Power,  Black Ground,  The BLUE wire is your trigger, connect it to a (-) instant trigger input on your alarm.  Does the red LED come on when the sensor "hears" a SSSSSSHHHHHH sound?  I've never see a bad 506T right out of the box.

I'm testing it by tapping on the glass with a key or a coin.  Harder and harder.  The mic is mounted in the far top left corner of the windshield next to the pillar.

I have the wires hooked up exactly like you said.  NO, the led never blinks.  It did for the first few seconds I had it connected but never since then.

Keep in mind that it's not plugged directly into the unit. It's spliced into the dome light trigger.  I'll recheck it all in the morning.  It's super easy to get to because it's inside the fuse panel cover on the far left end of my dash. 

I forget the exact wires I connected it to because it was installed a few months ago.  I assure you it was hooked up correctly.  I think you're right, it was the pin switch circuit and not the dome light.  I actually don't have pin switches on my doors other than the ones that activate the dome lights.  All I know is that it was connected to an Instant Trigger Input of the alarm unit.  So, the dome light ones are not considered Instant Trigger?  Oh, and I did use the correct 1-amp Diode as required in the instructions. There is an extra instant-trigger wire besides the dome light activated one, and I'm sure that's the one I hooked it to because it wasn't being used anyway.

As for the tapping, I didn't just tap it once and give up.  I tapped it several times, for the hour or so I tried to get it to work.  I remember how great my Ungo one worked.  One light tap would chirp the alarm, and a hard tap would set off the alarm.  This thing shouldn't require more than one hard tap to set off the alarm.  Hey, a rock or crow bar only contacts the glass once, and so it should go off with one tap.  I tried tapping many times with different thing. But you're right, the instructions say a single tap of a key or coin shouldn't set off alarm.

The good thing about all of this is that the proximity sensor works awesome, as does the instant activation with the dome light from each door as well as the shock sensor.  So I know the alarm unit itself is working fine.

All I know is that I should have just got a better alarm brand to begin with rather than buying a cheap one and having to add extra sensors and triggers and even the 3-into-1 thing just to accept added triggers. Heck, the alarm I bought for my last car was a Scy-Tek and it worked awesome.  The alarm was packed with sensors and features that this one doesn't have, and it only got me $55.  At that price I figured it was a cheap one until I checked their website and realized how highly advanced that company is.  I'm tempted to just rip this Omega alarm out and put in one of those $55 Scy-Tek alarms.  The only problem with them is that they take so long to install and adjust because of all the features.

I'll mess with it again today or tomorrow and let you all know what I found out.  It's disconnected right now so nothing is going to fry. I can always just run to the local stereo place today and buy a new and better sensor if I need to, but then I'd still have to hook it up the same way.  I'm just glad the shock sensor works with a bang on the windows or doors or body with a fist, and the proximity sensor works great (after countless re-adjustments of the sensitivity.

Thanks again, folks!

Yep, with my 35mm and fancy lenses, I can take pictures of a flea's nose! Okay, maybe not, but I can get pretty darn close.  But if you're going to tell me I will need to solder (spelling?) something, I'd be better off just buying a new sensor.  My soldering skills have never been very good.  An 8-year-old can do better than I can.  But I do have the gun and solder in case I decide to try.

Okay, here is the update:

I double checked my install on this sensor, and it was done correctly.  It was NOT actually wired to the dome light circuit or wire from the alarm box.  That was is BLACK/ white and is a negative trigger.  I didn't use this because I discovered that my pin switches, although they activate the dome light, were going to work because I have a negative dome light circuit.  When the door is opened, the switch completes a ground.  That's a negative input to the alarm box.  So, since I got a negative signal from my car's pin switch when I opened the door, I hooked the glass breakage sensor up to my alarm's negative trigger wire, which is blue.  How ironic, blue to blue.

So does this all make sense now?  Hope so.  No voltage was introduced into the sensor when the door was opened, hence nothing should have burned up.  It was simply completing a ground and thereby sending the negative signal to the alarm and setting it off.  The instructions for the sensor say to do it this way.

The other updates are as follows:

Yes, the red indicator light on the sensor comes on when I tap my ring of keys on the window.

I hooked my DMM to the blue output wire of the sensor, then checked it for voltage when I tested the sensor: it reads .01 volt every time I rap my keys on the windshield.  Which tells me I should hook it to my alarm's POSITIVE instant trigger wire rather than negative.  Right?

So, if you ask me (maybe you shouldn't) the sensor IS working correctly, but for some reason the alarm isn't picking up the signal correctly.  I wonder if maybe the diode is bad.  I bought the exact size diode that the manual stated: a 1-amp, purchased at a local electronics warehouse because Rad Shack didn't carry that size.  I do have extras.

I'll go out there and keep trying stuff and keep you posted.