Will this work (Diagram included)?

[Buffalosports]

I am going to add LEDs under my dash and also under the seats. I want the lights to turn on when I open the door but also I have a switch which makes the lights beat with the music. I want that to work also. Here is a wiring diagram I made quick. Do you guys see any flaws?

NOTE: I sacrificed one of the two cig. lighters. Cut the wires and thats my power source. I forgot to put on my diagram the fact that I have a fuse before the pig tail. Not sure if it will be needed with the resistors (?).

 

[Maniak]

At first glance, the only thing I see is you don't "need" the relay. It looks like your isolating the dome light signal from your street glow switch using the relay. Instead of using a relay put in a blocking diode to keep the power from the manual switch from back feeding into the dome light power.

in other words, you can take the relay out of the diagram (and power going to it).. and put the diode between the 12v from the dome light turn on and the output of the switch. Now when either is powered the light will turn on.


I don't know how much power your going to draw but if your running multiple lights and don't want the dome light fuse powering the LEDs then what you have drawn is fine BUT I would still put a diode between the output of the relay and the output of the street glow switch. That will keep 12v from the street glow switch off the ouput terminal of the relay.

someone else may have other ideas.

~Mark

 

[Buffalosports]

Well the reason I added the relay was because I do not want to draw a lot of power of the dome light. Then the dome light will be dim and they are barely bright enough now. I will probably end up adding the diode. The only thing I am worried about is if the switch is closed (lights on), and the door is open, will that put to much power into the circuit? Or will the resistor be able to hold the power back? After that question is anwered, is a fuse needed if the resistor is on the line? AND with that answered, will the resistor back the power up enough that it will pop the fuse (If I do need one on the line)?

 

[Maniak]

Well the reason I added the relay was because I do not want to draw a lot of power of the dome light. Then the dome light will be dim and they are barely bright enough now.

Leds take very little power.. How many are you installing.. If your installing a bunch then you should use the relay..

I will probably end up adding the diode. The only thing I am worried about is if the switch is closed (lights on), and the door is open, will that put to much power into the circuit? Or will the resistor be able to hold the power back?

You can put as much power as you want on it.. Your only adding Potential (voltage).. your not forcing amperage.. The amount of power you "pull" (amperage) is dermined by what load you have on the line which in your case is just LEDs. The Diode is to just to keep the power from backfeeding to the relay, which isn't "necessary" in your circuit, but is good to have. I've been somewhat lazy in my wiring recently and haven't been adding diodes to stop backfeeding to relays and the relays seems to be holding up fine.

After that question is anwered, is a fuse needed if the resistor is on the line? AND with that answered, will the resistor back the power up enough that it will pop the fuse (If I do need one on the line)?

You should fuse the 12v lines before the switch AND before the relay (the 12v from the cig lighter). Those are there to take power away if something bad happens (like a short in the wire)..

As for the right size resister.. There are charts that show what resister you should use. I've gotten lazy over time.. I just buy 12v indicator (led w/ build in resister) so I don't have to figure out the right size resister to use. That resister is there to limit the amount of amperage that goes through the LED.. the total amperage draw through the circuit is what you use to figure out what size fuse to use (don't use a fuse rated for higher than the wire or the wire will melt before the fuse blows)

~Mark

 

[Buffalosports]

I am adding 8 LEDs under the passanger's and driver's seat (4 under ea.). I am putting 5 LEDs under each side of the dash (10 all together). Also I may order tube lighting and run it between the celling and the plastic columns. I might but one or two series in the back.

For now, I am just doing the dashboard and seats (18 LEDs). The switch I have allows to connect up to 12 series. It actually has little screws (like on an amp) where to screw the wiring into but as stated, I want some to turn on when I open the doors.

Thanks for the help.

 

[BWilliams]

Buffalo, if you're really concerned about dimming your dome lamps because of current draw, consider converting them to LED as well -- I have 2 boards of 8 in the front, and an array of 6 in each the middle and cargo, and it's brighter then stock. You wouldn't have to worry about drawing too much power and dimming the lights since there's so little current draw from LEDs. (assuming you're wiring in parallel).

Also, if your LEDs are 3.3v forward voltage, you need 470 ohm resistors if you're using a single LED, or you can wire 3 LEDs in series with a 100 ohm resistor in front of it. If you're using LEDs with another forward voltage... hell if I know.

 

[shortstack]

you dont need a relay, led's use such little power that it wont even notice it hooked up, you would need to use over like 100+ for it to even matter