Fake car alarm LED installation

[robokop]

If anyone is really good with wiring for cars I'd appreciate some help with the following...

I recently replaced the factory stereo in my '04 Sorento LX and I would like to install a red flashing LED light (not a full alarm) to deter any potential thieves. I know this is not a new idea but I'm having trouble finding any detailed instructions on the web for this.

On a couple other forums there are people who mention parts that they bought from Radio Shack and installed successfully. The first one I read stated:

"I wanted the same fake alarm blinking led, went to Radio Shack and they fixed me up with the following parts and a basic wiring diagram..."
blinking led 3.0-3.8 volt part no. 276-312
led holder part no. 276-079
270-Ohm resistor part no. 271-1112
12vdc relay part no. 275-241




Another guy installed one on his motorcycle with the following parts:

5mm Blinking Red LED, #276-036
Panel Mount LED Holder, #276-080
1k Ohm Resistor, #271-1321



For some reason he didn't use a relay like the first guy did. Maybe its not needed for a motorcycle.

Anyway, the parts are inexpensive according to radioshack.com but I just don't know how this needs to be wired properly. I would prefer not to drain my battery or possibly have my car catch fire.

I tried asking a couple guys at Radio Shack but they didn't know a darn thing about it even though most of the parts I'm looking for were right there at the store they work at.

If anyone has done this set up I'd appreciate a detailed description on how to wire this. It shouldn't be that difficult but I don't know anything about resistors and relays. I'm sure there are other Kia owners that would like a little theft prevention without the cost and hassle of a full alarm system.

[CorvettePilot]

Why a fake???

[267]

all thats needed is an LED
connect + side of LED to perm live
connect - side of LED to ign live (live when ign is on )
ign on LED will be off
ing on LED will be on

best LED to use are LED from car alarms as they flash

[robokop]

Originally Posted by CorvettePilot

Why a fake???

I don't want a full alarm because I had one before that was a pain in the butt. It might have been the brand of the alarm but it didn't work properly and was oversensitive (motorcycles would set it off). Also, I like the existing key fob that came with the car and I don't really want to have to use a different one. I just want a bit of a deterrent for thieves. Usually if they just think there is an alarm they will move on to an easier target.

Originally Posted by 267

all thats needed is an LED
connect + side of LED to perm live
connect - side of LED to ign live (live when ign is on )
ign on LED will be off
ing on LED will be on

best LED to use are LED from car alarms as they flash

Thanks 267. The reason I wanted to use the resistor and the relay is because I have read that some people have have battery drain issues without them. Like the following site states:
Blinking Red LED Car Alarm Light

I don't want anything causing battery issues. It is probably easy to set up with the relay and resistor but I just figured someone out there would know how to do it properly so I don't wire it wrong.

[ron1004]

Originally Posted by robokop

Thanks 267. The reason I wanted to use the resistor and the relay is because I have read that some people have have battery drain issues without them. Like the following site states:
Blinking Red LED Car Alarm Light

I don't want anything causing battery issues. It is probably easy to set up with the relay and resistor but I just figured someone out there would know how to do it properly so I don't wire it wrong.

I would go with exactly the same method in that link.
You will need the volt dropping 270 Ohm resistor (the LED operates at + - 3 V), but I see no need for the 12V relay.
The example in that link uses a 470 Ohm resistor which would of course not be as bright as the 270 Ohm - why not try it with each resistor and see how bright you'd like it.

If you need to identify the LED leg they refer to as "the negative leg" - the LED has a small flat on the side of the negative leg (cathode).