i have a 2000 gmc jimmy door speaker wires?

[Big d]

i have a blue wire and a purple wire .o my right front door.. witch on is witch?

 

[Flip M]

you can tell by the wire itself. when you strip the end to wire it to something, the copper wire is neg. and the silver wire is positive

 

[Molson02536]

Believe purple is the positive wire. Good luck.