Moddiction

Hey wondering if anyone has ever tapped into power in the door panel for anything.
I am wiring up a red led for my interior door handle so people can find the handle when getting out.
I tried tapping into the speaker power from the door speaker but did not give power for some reason.
I don't have a multimeter at the moment. I did test the LED and it is good. Has a resister inline in the wire.
Can I wire into any of the switch plugs or anything?
Originally I was going to wire it up to the ebrake so it would only light up when the ebrake was pulled but seems much easier to just have it on all the time or something.
Was thinking of wiring into the cabin fuse box area so it would go on when the headlights are on but I use them pretty much all the time so would basically be the same just more work.
If anyone with some electrical knowledge could help out I'd appreciate it.

Js S2k

i dunno how hard it would be to do but i think it would be cool to wire it with the interior lights that come on when you turn the key back so you dont have a red led glowing all the time.

The speaker wire didn't work cause its only getting power when the music plays and also in the frequency of the music so definitely can't use that.

Moddiction

Well I don't really want it to come on with the dome lights cause then it would be pointless to have the door handle lights kind of.
I would like it the most if they came on when I pulled the ebrake which I'm sure can be done but will be a pain to wire it all the way to the center console.
I had the music on when I was testing it and didn't work. I think what I did wrong was I didn't ground the power to the door or anything just tapped into the lines.
I would have to ground the led to the door frame or something right?
So what would the outcome be using the power from the speaker? Would the light kind of blink or something or what?

Js S2k

I dont think it would work period from a speaker as its not a constant 12v source.
Wiring to the center console isnt as hard as you think.

The carpet comes up relatively easily and theres plenty of room to wire under the stereo, just follow the oem antenna wire.

Moddiction

Looks like a real pain to wire from the door to the cabin though. Looks like a bitch to wire through that wire cover thing by the hinge.
Ever do it?
I must be able to tap into the window switch harness no?

gofast182

You absolutely cannot wire into your speaker and you shouldn't be messing with stuff like that not knowing electronics. First of all, speakers have an impedance matched to the amplifier (head unit) and when you take into account the resistance of the LED and the pull-down resistor you could seriously damage the amplifier. Second, an LED is a diode so it needs a certain voltage present just to turn the damn thing on (let's say .7 volts for a typical diode) so any voltage below that, you've got no light. Since you're talking about an AC audio signal, not a DC voltage, that would mean the signal going to the speaker would have to be above that threshold to turn it on AND it would only turn on when the signal has positive phase. So assuming you've got the proper voltage for a given period and the amplifier isn't damaged, you may not even see the light because it's only on for about 33 nanoseconds at a time (assuming a 15kHz audio signal above +.7v).

Moddiction

Ah ok. So what about wiring into the window switch wiring? That should work no?

gofast182

Possibly, if you do it right. But you kind of need to know the current in that circuit because you need to make sure your pull down resistor is rated high enough to handle it. Also I'm not sure what the resistance of the window regulator is so depending on whether you had it in series or parallel could affect the way the regulator operates which wouldn't be good either.

Moddiction

Hmm yeah don't know the terms or anything really lol. Just know how to connect the things haha.
I'll try to find which wire is the power supply tomorrow for the window switch and give it a shot.
I would think it would work but I guess I'll have to find out.
If I just get a multimeter and check the connector and it shows 12v or whatever then I am good?
Also if it lights up and stays lit am I good then for power?

gofast182

I don't condone any of this so I'm not going to tell you potentially how to do it other than give you some theory. There's a lot of information missing and I don't want to see anything F-ed up with your car.

First of all what's the current rating of the LED? What's the current of the 12v window supply? Do the two fall within each other?

Multiply the current on the line times 12v. Does that at LEAST equal the power rating of your pull-down resistor?

Just because the light stays on doesn't nec. mean you're good without matching voltage and current tolerances (as I suggested above). You could be slowly burning up your pull-down resistor or the LED which could then short to the door frame.