Aftermarket Alarm Install

[movado75]

I just had a Compustar alarm installed and removed the keyless entry module from under the glove box. So here's the deal, even though the keyless entry is removed, the OEM security system is still active in the car if I lock the car with the key. The Compustar does not seem to be tied in to the OEM system and, thus, will not activate or deactivate it.

So here's a scenario. The Compustar is deactivated. If I lock the door with the key, the doors lock, OEM security system turns on, Compustar remains deactivated. If I then activate the Compustar, the door locks click (but remain locked, as they should I assume), big blue LED lights up showing me the Compustar is active, AND the OEM security goes crazy (lights, horns, etc. are set off) Obviously, the OEM security thinks the car is being broken into.

Now I guess if I just don't lock the door with the key, I won't have this problem, but it does annoy me and makes me think it wasn't wired properly.

Some options I've thought of are the following:

1. Have the OEM security wired to Compustar so that they are BOTH activated and deactivated when I activate and deactivate the Compustar (not sure how feasible that is).

2. Completely disable the OEM security.

3. Stop being so anal and leave it as it is.

I'm open to any other suggestions. What do you guys think?

 

[D'Ecosse]

Some options I've though of are the following;

1. Have the OEM security wired to Compustar so that they are BOTH activated and deactivated when I activate and deactivate the Compustar (not sure how feasible that is).....
I'm open to any other suggestions. What do you guys think?

I can help you with this - I need to run right now but will post up instruction later today

 

[Joseph]

here's the link,

http://www.nsxprime.com/forums/showthread.php?t=40550&highlight=factory+keyless+entry+question

 

[movado75]

here's the link,

http://www.nsxprime.com/forums/showthread.php?t=40550&highlight=factory+keyless+entry+question

Thanks for the procedure guys.

Joseph, how did the alarm install in your car go? Did you have any problems installing the relay?

 

[Malibu Rapper]

Going by my blurry memory of the OEM security system, I wouldn't think that locking the car triggers the alarm. I thought it was triggered by opening the door, trunk, hood, etc, not by a locking action. Can't search the manual right now but seems odd that it would go off from a locking action. I'll look into it a little more when I get the manual in front of me.

But I think you might not even need to do anything. I don't like to use my key at all because it inevitably leads to scratches around they keyhole. So if your alarm can lock your car up, why not just let it do so and not use the key?

 

[Zennsx]

Sounds like one of the commom trigger points (door pin switches etc) could be at or near ground potential for a brief instant when the compustar alarm is activated thus triggering the OEM alarm. Without a detailed schematic of how the alarm is installed it would be tough to diagnose.

 

[movado75]

So here's a scenario. The Compustar is deactivated. If I lock the door with the key, the doors lock, OEM security system turns on, Compustar remains deactivated. If I then activate the Compustar, the door locks click (but remain locked, as they should I assume), big blue LED lights up showing me the Compustar is active, AND the OEM security goes crazy (lights, horns, etc. are set off) Obviously, the OEM security thinks the car is being broken into.

OK guys, my apologies. I just went to check the above scenario and the OEM security doesn't start going crazy until I disarm the Compnstar, which makes a lot more sense! So installing the relay should solve my problem.

Sorry guys, I hate giving the wrong information. You guys have been really helpfull !

I asked the place that installed the Compstar if they could install this relay and they wouldn't even go there. Liability I suppose, which I can understand. Do any of you guys know someplace or someone in Socal who would do this? I could probably do this myself, but am a bit hesistant. They would be compensated of course.

 

[Joseph]

Thanks for the procedure guys.

Joseph, how did the alarm install in your car go? Did you have any problems installing the relay?

sent you a pm

 

[D'Ecosse]

I had forgotten I had done that drawing too! I originally did mine (actually is still like this) with just a couple of diodes. Another member was having trouble making his work & I suggested the relay method as an alternative - he still couldn't get it to work so I think there were maybe some execution problems at his end!

Here's a simpler mothod - just pick up a couple of 1N4001 diodes at Radio Shack.

 

[D'Ecosse]

p.s. There are two wires coming into security module from the keyless entry - the brown & grey wires - I can't be 100% certain because I don't have access to the OEM keyless entry module schematic, but I'd be willing to bet that you could connect those inputs to use as the arm/disarm triggers from the after-market brain.

Also, as to original problem -

So here's a scenario. The Compustar is deactivated. If I lock the door with the key, the doors lock, OEM security system turns on, Compustar remains deactivated. If I then activate the Compustar, the door locks click (but remain locked, as they should I assume), big blue LED lights up showing me the Compustar is active, AND the OEM security goes crazy (lights, horns, etc. are set off) Obviously, the OEM security thinks the car is being broken into.....

That definitely shouldn't be happening in any case - something is wrong to cause that to happen. It's hard to perceive without knowing how your installer wired things to determne remotely what would cause this unfortunately

 

[Malibu Rapper]

OK guys, my apologies. I just went to check the above scenario and the OEM security doesn't start going crazy until I disarm the Compnstar, which makes a lot more sense! So installing the relay should solve my problem.

Sorry guys, I hate giving the wrong information. You guys have been really helpfull !

Ok, it's starting to make a little more sense. But I think you might be leaving one important detail out if I can make an assumption that your factory alarm doesn't go off until you open a door, not just by you disarming your alarm and unlocking the doors. If that is the case, then it all makes sense. When you lock your car with the key, that arms the factory alarm. When you disarm your car with the alarm remote, that unlocks the car without disarming the factory alarm. The factory alarm is disarmed by sensors in the trunk and door keyswitches which sense key in UNLOCK position.

I don't know about the Compustar alarm, but my Crimestopper alarm has a OEM factory alarm disarm output. I wired this to the green/yellow wire on the OEM security alarm harness (the smaller harness). Both green/yellow wires are good to use, one is for the driver door and the other is for the passenger door. The Crimestopper alarm sends a ground when disarmed so it works perfectly. The green/yellow wire is the key in UNLOCK sensor wire.

Your alarm MIGHT have this output wire. Do you have the install manual? If it does have this wire, go back to the shop and tell them to hook it up like I described above. If it does not, they could easily wire in a relay to send a ground when the car is disarmed.

None of this would be a problem if the key is not used to lock the car because the OEM alarm does not arm if you do not lock the car with the key. If it doesn't arm, it doesn't go off. A lot of NSX alarms I've seen are installed like this, the OEM alarm will go off if they ever armed it. But to do it right, you should disarm the factory alarm at the same time the Compustar alarm is disarmed.

 

[D'Ecosse]

OK - yes, that helps explain things a little

I asked the place that installed the Compstar if they could install this relay and they wouldn't even go there...... I could probably do this myself, but am a bit hesistant.....

Odd that they wouldn't wire this - really simple for any alarm shop to consider.

See my link above - this is DEFINITELY easier than installing the relay which is slightly more complex and you may feel more confident in doing this by yourself - link for the diodes was given above. Cheaper too - only $0.59 for a pair of diodes!

Whether or not your alarm does have an OEM disable (mine is Crimestopper too, like Malibu Rapper's - I use that output for OEM alarm disable for the remote starter), the circuit referenced in my post above is actually most efficient means to arm/disarm the OEM security system - minimal length of wires to run & it can all be done right there at the connectors shown without having to go back to the After-market brain at all (which is probably located on other side of the car)

The actual electrical schematic which corresponds to the wiring diagram above is as below. It utilizes the lock knob position inidcator switch to set/reset the OEM alrm via keyswitch inputs.

 

[Malibu Rapper]

Whether or not your alarm does have an OEM disable (mine is Crimestopper too, like Malibu Rapper's - I use that output for OEM alarm disable for the remote starter), the circuit referenced in my post above is actually most efficient means to arm/disarm the OEM security system - minimal length of wires to run & it can all be done right there at the connectors shown without having to go back to the After-market brain at all (which is probably located on other side of the car)

Yep, this method would work, too. A few drawbacks though. The OEM alarm will always arm whenever the power door lock unit is used to lock the door. This changes the way the Honda engineers wanted to arm the alarm by using the door key sensors. So your potential problems are if the car is locked using either power door lock switches or via the actual door lock knob on the driver side (which sends a power lock signal), then if the doors are opened w/o using the power door lock or if the trunk is opened using the button on the door, then your alarm goes off. I think the Honda engineers did their best so that these situations wouldn't happen, even though they are rare. In addition, many thieves break into cars by bending out the windows and unlocking using the power door lock switches (ask me how I know). The factory alarm would be disabled via the door lock switches. In this case, you would have the aftermarket alarm to contend with but if you are keeping the factory alarm, you've greatly diminished it's value and might as well keep it out of the whole equation.

I would recommend hooking up an OEM alarm disable to keep things status quo. You alarm might already have this wire or you could easily have them wire a relay to do this. Arming the factory alarm would still be optional. But if you wanted to arm it every time, then you could use a pulse when armed (or even starter kill relay wire) from the aftermarket alarm to arm the OEM alarm. Remember, you paid the shop to have them do this alarm right. They should do this for nothing if they are reputable.

 

[Zennsx]

Sounds like the installer didn't connect the lock unlock inputs into the cylinder switch wires. On several occasions I have locked my car with my key and left my windows open. Upon returning to my car I would reach inside my car and hit the unlock switch and Voila ,Alarm would sound.

 

[Malibu Rapper]

Sounds like the installer didn't connect the lock unlock inputs into the cylinder switch wires. On several occasions I have locked my car with my key and left my windows open. Upon returning to my car I would reach inside my car and hit the unlock switch and Voila ,Alarm would sound.

That should not happen if you only unlock. We're talking about the factory alarm going off right? You've got something else going on if the door unlock trigger is setting off the alarm. I'm looking at my 95 manual in front of me, and here are the triggers:

1. Door is opened forcibly
2. Engine compartment lid is opened
3. Trunk lid is opened without using the key
4. Hood is opened
5. Roof is unlatched (NSX-T "Open Top")
6. Battery terminal(s) is (are) removed and reconnected
7. Engine starter circuit and battery circuit and bypassed by breaking the ignition switch
8. Hood/engine compartment lid/trunk lid opener or roof release lever (NSX-T "open top") in the vehicle is operated

Unless the earlier cars included such a trigger, your alarm should not go off when you unlock. If you unlock and then open the door, that should trigger it.

 

[D'Ecosse]

... The OEM alarm will always arm whenever the power door lock unit is used to lock the door. This changes the way the Honda engineers wanted to arm the alarm by using the door key sensors. So your potential problems are if the car is locked using either power door lock switches or via the actual door lock knob on the driver side (which sends a power lock signal), then if the doors are opened w/o using the power door lock or if the trunk is opened using the button on the door, then your alarm goes off. ....

OK - I need to investigate a little further as to what I actually did - need to open up my glove box to check for sure how I did this (drew the schematic based on my recollection & thought that's what I did!)

When testing just now, verified that OEM alarm sets with the power remote of the after-market; however when inside the car & either using the power lock switch, or just manually depressing the button, it does not set the OEM alarm. So it appears I did something different! LOL - I'll report back tomorrow when I have time to validate!

 

[Malibu Rapper]

Well you learn something new everyday. I just validated what Movado75 and Zennsx were saying. I armed my factory alarm and unlocked with the switch and it does indeed trigger the alarm. It's an undocumented feature.

One other trigger in my service manual not listed with the first 8 is in a flowchart. If the stereo is disconnected, it will also trigger the alarm.

The solution is still the same, you need to pulse a ground to either green/yellow wire on the security unit to disarm the alarm. Fun stuff.

 

[Zennsx]

That should not happen if you only unlock. We're talking about the factory alarm going off right? You've got something else going on if the door unlock trigger is setting off the alarm. I'm looking at my 95 manual in front of me, and here are the triggers:

1. Door is opened forcibly
2. Engine compartment lid is opened
3. Trunk lid is opened without using the key
4. Hood is opened
5. Roof is unlatched (NSX-T "Open Top")
6. Battery terminal(s) is (are) removed and reconnected
7. Engine starter circuit and battery circuit and bypassed by breaking the ignition switch
8. Hood/engine compartment lid/trunk lid opener or roof release lever (NSX-T "open top") in the vehicle is operated

Unless the earlier cars included such a trigger, your alarm should not go off when you unlock. If you unlock and then open the door, that should trigger it.

Check the wiring schematic pages 11. The cylinder lock outputs are in parallel with wires going to the security control unit. Try this test on your car and I bet your alarm will sound.When I looked at the schematic I always wondered why the door lock unlock outputs weren't simply wired in parallel with the cylinder switch outputs.

 

[Zennsx]

Another thing is to make sure the installer uses the passenger cylinder switch outputs to unlock the doors otherwise only one door will unlock (drivers side) .

 

[Malibu Rapper]

Check the wiring schematic pages 11. The cylinder lock outputs are in parallel with wires going to the security control unit. Try this test on your car and I bet your alarm will sound.When I looked at the schematic I always wondered why the door lock unlock outputs weren't simply wired in parallel with the cylinder switch outputs.

You're absolutely right about the alarm going off. Thanks for the correction. But, the cylinder lock outputs going to the security does not make it a trigger. Looking at the security control unit gave me a clue as to why this was happening. There are two Blue/Red wires which sense the driver and passenger door lock knob in unlock.

So to test this, instead of using the switch to unlock the doors, I used the passenger knob. Pulling it up triggers the factory alarm. Seems somewhat undocumented in the alarm documentation but it probably falls under the category of "Door forcibly opened."

Which gives me another thing to do on my tasks list next time I work on the alarm. I can wire an instant trigger to the blue/red wires to my aftermarket alarm. Not many cars have sensors built into the doors to sense the unlock position and this gives an additional security sense.

Lots of good info being uncovered on this thread...

 

[Zennsx]

That should not happen if you only unlock. We're talking about the factory alarm going off right? You've got something else going on if the door unlock trigger is setting off the alarm. I'm looking at my 95 manual in front of me, and here are the triggers:

1. Door is opened forcibly
2. Engine compartment lid is opened
3. Trunk lid is opened without using the key
4. Hood is opened
5. Roof is unlatched (NSX-T "Open Top")
6. Battery terminal(s) is (are) removed and reconnected
7. Engine starter circuit and battery circuit and bypassed by breaking the ignition switch
8. Hood/engine compartment lid/trunk lid opener or roof release lever (NSX-T "open top") in the vehicle is operated

Unless the earlier cars included such a trigger, your alarm should not go off when you unlock. If you unlock and then open the door, that should trigger it.

After reading how thorough the OEM alarm is ,Why would anyone install an aftermarket unit?? The only additional features an aftermarket system has is a different siren-command chirps and or blink indicators.

 

[Malibu Rapper]

After reading how thorough the OEM alarm is ,Why would anyone install an aftermarket unit?? The only additional features an aftermarket system has is a different siren-command chirps and or blink indicators.

I'm pretty surprised how many triggers the OEM alarm has. Good enough for most people but aftermarket has a LOT of advantages.

1. Accessory outputs (ie. window controls, remote start, etc)
2. Code hopping
3. Remote 2 way capability for notification via paging
4. Easy to add extra sensors
5. Ignition controlled door locks
6. Auto-arming (or not depending how programmed)

Those are just a few. But the OEM system is pretty good security by itself.

 

[Zennsx]

You're absolutely right about the alarm going off. Thanks for the correction. But, the cylinder lock outputs going to the security does not make it a trigger. Looking at the security control unit gave me a clue as to why this was happening. There are two Blue/Red wires which sense the driver and passenger door lock knob in unlock.

So to test this, instead of using the switch to unlock the doors, I used the passenger knob. Pulling it up triggers the factory alarm. Seems somewhat undocumented in the alarm documentation but it probably falls under the category of "Door forcibly opened."

Which gives me another thing to do on my tasks list next time I work on the alarm. I can wire an instant trigger to the blue/red wires to my aftermarket alarm. Not many cars have sensors built into the doors to sense the unlock position and this gives an additional security sense.

Lots of good info being uncovered on this thread...

The cylinder lock outputs dont trigger the alarm, what they do is arm-disarm the alarm via keyswitch:wink:

 

[movado75]

Wow, looks like there was a lot of activity on this thread over the weekend. Thanks for all the info guys! I checked with Compustar and the alarm DOES have a factory arm/disarm output. I definitely want the factory alarm to arm and disarm with the Compustar. I think my best bet would be to have the arm/disarm output from the Compustar hooked up to the factory alarm. Does someone have a schematic for that set-up?

 

[D'Ecosse]

Wow, looks like there was a lot of activity on this thread over the weekend. Thanks for all the info guys! I checked with Compustar and the alarm DOES have a factory arm/disarm output.....

Can you confirm please - does it have both factory arm & disarm outputs, or just disarm (more likely)?

Edit - never mind! Looks like both.

http://www.compustar.com/additional_features.htm

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