Are you sure? I have one of the first ones and the trigger wire is +
have you tried it out? They're diodes, you you arent gonna break it if you hook it up wrong
Has anyone installed one of the Varad Alarm LED's, either the single one or the scanners? Specifically in a car without an aftermarket alarm.
I'm confused by the instructions.
There's the usual red and black for + and -, but the trigger wire is -.
The Varad rep told me to hook it up to an ignition wire, and that when you turn off the ignition, that wire will become a ground.
Is there such a thing as a positive that switches to negative on any cars?
Anyway, I know there's obviously ways around this, with relays and such, just trying to figure out if there's a fool-proof way to install these without having an alarm.
Yea, the reason behind this post is I work at a parts store and we've started selling them. I wanted to see how bright they were, so I tried hooking it up. The old brand of fake alarm LED I carried used a transistor to turn it off when + was supplied to the trigger wire, thus turning on when the IGN was off. I tried wiring it like that (just hooking up red and black). No go. In desperation, I tried various combinations and got it to turn on when I grounded the black and yellow (orange in the newer models) and powered the red wire. I canned our Varad rep and he confirmed the trigger was -. He said, like it made perfect sense, that the ignition wire did in fact switch to ground when you turn the car off. I don't know enough about modern car wiring to argue with authority, so I said I understood.
Now thinking about it, there should be no need for an ignition wire to ground out when turned off. It's simply dead when it's off. I mean, check the polarity of the output of a toggle switch when it's turned off. It's simply off, not + or -. Why would an ignition switch be different.
Please, someone prove me wrong, I can't think of any other reason why Varad would wire their LED's that way.
Again, for an alarm, most of them have negative outputs, so that's not such an issue, but they state on the packages for use with or without an alarm. A lot of my customers have no idea how to hook up a relay.
Sorry for the long posts, this has been bugging me for some time now, I had to vent or I'd explode.
[Edit for typo]
.......(getting the instructions for Varad Headlight Flashers from my car)
You're thinking of the ignition switch in isolation from the rest of the circuit. The ignition switch doesn't ground out itself. But it has a bunch of devices between it and ground on the output, so that when the 12v is removed, the ignition line is effectively grounded through those.Originally Posted by Superduck
OK straight from the instructions for Varad's Headlight Flashers (2 LEDs, one per headlight)
A black box is in the middle, with 2 wires running to single LEDs runs out one end. On the other end of the box, FOUR wires:
RED - Battery or constant 12V (POSITIVE)
YELLOW - Ignition (Deactivates HyperLED when positive 12V is applied)
BLUE - Head Light positive 12V (Turns LEDs on constantly)
BLACK - Ground
Blue wire's purpose is to have the LEDs on while driving, which gives off a bluish tint to headlight housings (I have it hooked into my fogs) The blue can be omitted if you don't want the lights on while driving, and only when the cars ignition is OFF...
Hope this helps
Okay, I really want to wrap my head around this. There is at least one wire in any given car (or even one specific, that is + at some point, then when "turned off" becomes - ?Originally Posted by Rob Withey
How can you run the same wire to a ground? As soon as you activate the switch, it's going to short to the ground and fry something.
I have to admit, I don't know the inner workings of an ignition switch, but on my car, my alarm has a + out to the ignition switch for the remote start.
That's how our old fake alarm LED's worked, so they weren't flashing while the car was running. And supposedly, that's how the old Varad's worked too, according to Wizard. So, in theory, if you just connect the red and black, it should start flashing. When I connect the trigger to + source, it will stop flashing. Alas, that doesn't work. It won't flash until both the trigger and black wires are grounded, and the red has power.Originally Posted by FiSKARZ
It's basically the idea that the ignition wire (I think there's only one or two in any given car) switches to ground that I don't get. So if I take a test light, connect one end to the positive of the battery, and the other end to the ignition wire, while the car is off, it will light up? Somehow, I don't think that will happen. Electrical common sense would say otherwise.
I don't get how the Varad guys haven't had people complain yet. Maybe if I actually tried it myself, it might work and this will have been a complete waste of time.
Thanks for the help so far, people.
The line doesn't become ground. It is "effectively" grounded through the loads on the output (eg, your radio, your electric window controller, your central locking controller, your airbag controller, your ecu, etc). It is not a short, there is a resistance there (the load of the devices) but since there is no current flowing, there is no voltage drop (V=IR). Therefore the ignition line is "effectively" grounded. The current draw on the trigger wire of the Varad is tiny, and not enough to put any appreciable voltage drop in.Originally Posted by Superduck
When you switch on the ignition, those devices all get their power and the right amount of current and everything is fine (and the Varad sees +12v).
The same wire is run to ground _through_ the devices on the output of the ignition switch. It is not shorted. An ignition switch is just like any other switch, except that it has a bunch of poles, some momentary (starter) and some non-momentary (accessories, ignition).Originally Posted by Superduck
It doesn't, I never said it did. It's the loads on the output of the ignition line that ground out (not a short though, it's the resistance of their load).Originally Posted by Superduck
Sure, but you have missed the point and your electrical common sense is incomplete.Originally Posted by Superduck
Please do try this. Just put a volt-meter between the ignition line and the permament 12v line of the battery and you'll see.Originally Posted by Superduck
You're welcome.Originally Posted by Superduck
this subject is one of the weirdest things to understand. when i was an installer i trained guys to always test the factory ground wire in the dash - if there was one - by turning on the lamps. you see, you are checking the middle of the wire. on one end you have the lights in the dash and the other end has 12v applied to "complete" the circuit. when you dont have the 12v on it you just have a circuit to ground through the lamps.
hope this helps.