Question about installing a LED Scanner Light to factory alarm.
07-18-2011, 12:05 AM
#1
Question about installing a LED Scanner Light to factory alarm. Its a Varad LED scanner light, I would like to hook it to the stock alarm on my 1999 trans am. Seems straight forward, red wire goes to constant 12v power, black to good ground. But where in the stock wiring of car do I connect the yelow wire so the scanner led turns on when the car is armed???
Thanks in advance for any help, here's a pic of the led scanning light:
Thanks in advance for any help, here's a pic of the led scanning light:
07-18-2011, 07:46 AM
#2
I don't think it will work. The LED scanner expects a simple on/off condition to control the light. The factory alarm LED circuit produces a flashing current rather than a steady current so your scanner would only flash on and off - it wouldn't scan back and forth like you'd expect.
If you want to try it, the wire is the dark green in position C16 of the 32-pin blue connector at the BCM.
If you want to try it, the wire is the dark green in position C16 of the 32-pin blue connector at the BCM.
07-20-2011, 08:06 AM
#5
It's easy enough to test for yourself. Just open the hood, connect the red wire to the battery positive, the black wire to the battery negative, and then touch and release the yellow wire on the positive terminal in one second intervals to simulate the pulse signal from the factory alarm.
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07-20-2011, 11:03 PM
#8
Is there anyway to activate the scanner when the car is armed? Any wire on the keyless module or bcm that I can tap into to make it work? I haven't got time to play with it, should have some time this weekend. I was thinking.... what if I try to wire in a relay and see if it'll turn it and make it stay on until disarmed?
07-24-2011, 11:18 PM
#9
Well, I tried it and it does not work as it should. Some how the scanner its activated by a ground when armed. I would need a dead wire that turns into ground when armed in order for the led scanner to come on and stay on until disarmed. Any more ideas??? 
07-25-2011, 07:42 AM
#10
You could add a Hornet 727T or Viper 330V alarm upgrade. These are designed to add alarm capabilities to cars with only keyless entry from the factory but they work fine on f-bodies even with a factory alarm (you just have to program the factory alarm not to arm). The kits offer additional features such as a real alarm siren and the capability to add additional accessories such as a motion detector while still using the factory remote key fobs. The big advantage here is that it has a "grounded while armed" wire that could be used with your LED scanner. I put one in my car many years ago - installation was easy and it's still working well. You can find them online for under $100. I wouldn't spend that just to connect an LED but the alarm features are well worth the price.
07-31-2011, 02:36 AM
#15
i had a similar scanner from varad but hooked it up to the fuse block on the driver's side of the dash. the red wire went to the BATT circuit and the yellow to the IGN circuit then grounded it to the ground above the hood release. it worked pretty well as a deterrent. every time the ignition was off the scanner would light but when the ignition was on the scanner was off. i did it this way for ease of install and wanting to be easily removable. the stock alarm remained untouched.
08-01-2011, 01:52 AM
#16
i had a similar scanner from varad but hooked it up to the fuse block on the driver's side of the dash. the red wire went to the BATT circuit and the yellow to the IGN circuit then grounded it to the ground above the hood release. it worked pretty well as a deterrent. every time the ignition was off the scanner would light but when the ignition was on the scanner was off. i did it this way for ease of install and wanting to be easily removable. the stock alarm remained untouched.
08-01-2011, 03:49 PM
#17
TECH Addict
A pulsed signal can always be made into a constant signal with a couple of transistors and a capacitor with the caveat that the scanner would remain powered for a little bit after the alarm is deactivated (for probably about 3-5t, where t is the length of time between the pulses). With the right wiring diagrams, though, there may be a way to figure out where to tap a signal that would be even easier to use than the power to that LED...
08-02-2011, 12:31 AM
#18
A pulsed signal can always be made into a constant signal with a couple of transistors and a capacitor with the caveat that the scanner would remain powered for a little bit after the alarm is deactivated (for probably about 3-5t, where t is the length of time between the pulses). With the right wiring diagrams, though, there may be a way to figure out where to tap a signal that would be even easier to use than the power to that LED...
08-02-2011, 09:11 AM
#19
TECH Addict
Here's one of the most basic versions of a capacitor buffer: http://imageshack.us/photo/my-images...torbuffer.png/ (yay MSPaint)
The transistors there are general purpose N-channel FETS (chose them over NPNs because they have higher input resistance, but you can substitute an NPN in if you want. Technically the schematic symbol I used is for a JFET but a MOSFET will also work - Radio Shack has IRF510s that are good). You can use a small transistor for the first one, like subbing an NPN like a 2n3904 or 2n2222, as they should be cheaper. For resistor and capacitor values, play around with them to get the period that you need. You can put a trimpot (large, like 100Kohm) in parallel with the capacitor to give you the ability to adjust it easily. Basically, the larger the capacitor, the longer the charge will last. Too small a value and the scanner will turn off between pulses. Too large and it could stay on for a long time after you disarm the alarm. I won't recommend values because I'd need to take some measurements to be able to properly do it.
The transistors there are general purpose N-channel FETS (chose them over NPNs because they have higher input resistance, but you can substitute an NPN in if you want. Technically the schematic symbol I used is for a JFET but a MOSFET will also work - Radio Shack has IRF510s that are good). You can use a small transistor for the first one, like subbing an NPN like a 2n3904 or 2n2222, as they should be cheaper. For resistor and capacitor values, play around with them to get the period that you need. You can put a trimpot (large, like 100Kohm) in parallel with the capacitor to give you the ability to adjust it easily. Basically, the larger the capacitor, the longer the charge will last. Too small a value and the scanner will turn off between pulses. Too large and it could stay on for a long time after you disarm the alarm. I won't recommend values because I'd need to take some measurements to be able to properly do it.
08-02-2011, 11:12 PM
#20
Here's one of the most basic versions of a capacitor buffer: http://imageshack.us/photo/my-images...torbuffer.png/ (yay MSPaint)
The transistors there are general purpose N-channel FETS (chose them over NPNs because they have higher input resistance, but you can substitute an NPN in if you want. Technically the schematic symbol I used is for a JFET but a MOSFET will also work - Radio Shack has IRF510s that are good). You can use a small transistor for the first one, like subbing an NPN like a 2n3904 or 2n2222, as they should be cheaper. For resistor and capacitor values, play around with them to get the period that you need. You can put a trimpot (large, like 100Kohm) in parallel with the capacitor to give you the ability to adjust it easily. Basically, the larger the capacitor, the longer the charge will last. Too small a value and the scanner will turn off between pulses. Too large and it could stay on for a long time after you disarm the alarm. I won't recommend values because I'd need to take some measurements to be able to properly do it.
The transistors there are general purpose N-channel FETS (chose them over NPNs because they have higher input resistance, but you can substitute an NPN in if you want. Technically the schematic symbol I used is for a JFET but a MOSFET will also work - Radio Shack has IRF510s that are good). You can use a small transistor for the first one, like subbing an NPN like a 2n3904 or 2n2222, as they should be cheaper. For resistor and capacitor values, play around with them to get the period that you need. You can put a trimpot (large, like 100Kohm) in parallel with the capacitor to give you the ability to adjust it easily. Basically, the larger the capacitor, the longer the charge will last. Too small a value and the scanner will turn off between pulses. Too large and it could stay on for a long time after you disarm the alarm. I won't recommend values because I'd need to take some measurements to be able to properly do it.