so I want to run two different led lights into the doors, one for a puddle light and another for something else. I already drilled out the molex for the door speakers and ran some extra wires for jdm folding mirror functions and speaker wires. I do not have enough wires run through the door for the lights but I am actually opting out of using the tweeters in the factory location and ran new speaker wire for the door so I have two wires free.

So what I am wondering is, can i use both the free wires as power leads, one from the dome light and the other from the other source and just ground the end of the lights to one of the grounds shared by the door's main harness. like instead of running a pos and neg both tapped to the dome light, just tapping the pos and then grounding to some random ground that is already running through the door harness. Could this potentially lead to any electrical issues? I figured since they were all just ground back to the chassis it would all be the same.

anyone care to clarify? im sure its a super simple answer.

thanks guys,
chris

 

Chris,

It depends on how much additional current you plan to draw, and how much current is already on the grounds that you intend to use as double duty. You could easily overdraw the current on the power side or the ground side, which would lead to blown fuses or worse.

Note that the stock tweeter is not meant to handle much power to begin with, so I'm guessing the wires would be small to begin with. It would be enough for a typical low-power LED, but we wary of internet strangers giving you affirmative advice one way or another without all the exact specifications.

Also worth considering - not all automotive electronics are always switched on the power side. They are almost always fused on the positive side, but sometimes switched on the ground side. I only mention this because you are considering sharing a ground with something else that goes to the door..

 

thanks so much for the answer. the tweeters and speakers actually share the same wire going back to the amp, people have run 100+ watts with just the stock speaker wires so im assuming it should be sufficient for a low power light. but yeah what you say about the grounds makes sense.

so the safest thing would be to tap both pos and negative? could tapping those wires over draw it as well? what would be the best way to tap additional lights into the dome lights? or tap dome light for power and then make a new ground to the chassis?