adding LED to factory security system

 Does anyone if it is possible to add an extension LED to the factory keyless entry/alarm system on a 2002 GMC Sierra 2500HD? It has the security light in the instrument panel, but i'd like to add an LED that is visible from outside the vehicle. There is a black plastic piece on top of the dash that resembles a large LED, but i'm not sure what it is.Any help would be great!:errr:

i think that is for your DRL.

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Good Luck
David
Ace Security
813-376-9778
Tampa
Donate to the 12volt

I don't know how to make an LED work with the factory system, but you could just use a relay to turn an LED off when you turn the ignition on and make it flash when the ignition is off. Varad also something that does that without the use of a relay.

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"Drive it like you stole it"

This security light in the instrument panel, is it a regular light or is it an LED? Does it flash or ??
Also, if you can access this light, can you measure with a meter and see if they are switching ground to it or +12V to it to make it light (most likely one side is constantly grounded). This info is needed to figure out the solution.

Thanks for the replies guys! Thinkster-the security light is sort of built into a small "message center" display. It has a dot matrix looking LCD screen. I think i'll try checking some wires around there with a DMM and see what I come up with.

Well, if you think about it, the LED you want to add doesn't specifically have to be built into your security system, does it? All you probably really care about is deterring thieves.

Go to an electronics store or Radio Shack or wherever, and buy yourself a 12-volt, flashing LED. It must be a flashing one; make sure.

Somewhere in the car, find yourself two power sources: One that is postive all the time, and one that is positive only when the key is on. You can find these behind the radio, or at the steering column, or possibly at one of the wiring plugs in the fuse box.

Connect the LED's positive lead into the constant power wire. Connect the LED's negative lead to the wire that only shows power with the key on.

Here's how it works: When you're driving, both of the LED's wires see positive power; therefore, the LED won't work, since there's no ground.

When you shut the car off, the other wire loses its positive power, and starts to look like a ground. It's an imperfect ground of course, but it is plenty good enough, since LEDs draw almost no current. So when your car is off, the LED sees power and ground like it needs to, and therefore it'll be flashing.

So all you need is one simple part--the flashing LED. And you only have two connections to make.

Also, realize that you want to be sure your job is protected by fuses, in case any of your LED wires should short out. If you make your connections at the radio, you should be pretty safe, since the radio is already protected by small fuses.

If, instead, you use the heavy-gauge wires at the steering column, you should add fuses of your own. The wires at the column are already supplied by 50-amp fuses under the hood.....but if your LED wires shorted to ground, the large fuses would not blow at all....rather, the LED wires would melt and possibly catch fire. If you're connecting at the column, it would be wise to put 5-amp inline fuses on BOTH of the LED's wires for protection.

Any idea on what wires to use for the constant positive and the positive thats only on with the key turned?? I dont have much experience at allll when it comes to wires, but I was looking to extend an extra LED to my dash with my alarm, but this way seems much easier. Thanks. I just need some examples of wires to use.

Constant 12 volts RED & RED / WHITE IGNITION SWITCH HARNESS
Ignition 12 volts PINK IGNITION SWITCH HARNESS


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Good Luck
David
Ace Security
813-376-9778
Tampa
Donate to the 12volt

I dont really know how to break into the wires? I looked up my car's info and found the wires for "Constant 12V+" and "Ignition". I found them under the dash but how do I connect the LED to the wires? Do I have to cut it totally and somehow wire the LED on there and then put it back together somehow? I dont want to mess up arguably two of the most important wires in my car. Thanks

Here's how you connect to the wires, and you don't have to cut them totally.

-First, you have to get the insulation off. I use a really nice wire stripper that makes things quick....but do you have a razor blade? Get just a plain blade, the kind you can hold in your fingers.

Take the blade, and make a cut that goes all around the wire's insulation...just go through the insulation, not the wire. Make another similar cut about 1/2" away. Next, make a lenghtwise cut between the two. Now you should be able to pull the insulation off; it'll come off like a 1/2" tube.

You should take a test light, or an awl, or even a nail...push the tool right through the middle of the wire so that it spreads apart.

Take the new wire (from your LED or fuseholder) and push it through the opening you made. Then wrap it around tightly a few times. You should be able to pull on your new wire without it falling off.

Soldering: Everyone recommends soldering, and that would include me too. But your LED will not be a critical component....if your connection fails, the LED will stop working but you can still drive your car....so you can get away with not soldering if you wish.

Hold your LED's wire so it's running parallel to the factory wire, and wrap tape around them both, very tightly. Use good tape (like something from 3M), not the 50-cent stuff that will fall off.

If you have them, take some zip ties and tie them around the tape...this will hold the wire in place stronger, and also help prevent the tape from falling off.

Tips:
-Whenever you're using metal tools on the wire (razor, awl, etc), be sure you don't touch your tool to the car's body at the same time....this will make unpleasant sparks and possibly blown fuses.

-When you're working on the pink ignition wire, do so with the key off....this way, even if you do short it out, nothing will happen.

-If there is body metal around your work area that you feel is impossible not to bump into with your tools, pus some duct tape over the metal for protection.

-Definitely don't forget my remark about using small inline fuses on both wires, especially if you're new to this.

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