I’ve got door cards with no tweeters and i wanted to buy ones with some. Is there a wiring harness that needs to be bought with the panels for the tweeters? Or do i just splice from the lower speakers to give power?

 

You can just splice from lower door speaker, but you'll want to add a high pass crossover.

You don't want tweeter trying to produce all sound frequencies, just the high pitched ones. A High Pass crossover filters out the lower frequencies. Bass and mid, and only passes the high frequencies to tweeter.

Stock there is a HP crossover in the door harness.

Any stereo place will sell them, as will Crutchfield.

 

Stock just has a cap mounted on the tweeter.

 

I usually see 5 to 10mfd/50 to 100VDC rated non-polar cap in one line to an 8-ohm car tweeter.

 

yep, it's glued to the tweeter.

 

A cap in series acts as a high pass filter