Rear speaker wiring

Hi,

Can anyone tell me which colour wire is the positive and negative for the rear speakers in a 1997 300tdi please... ta muchly

The wire with the black line or all black is usually the neg.

Oooh, be careful!
Been looking at this recently (sub woofer) Haynes wiring diagram shows black wire pos & black with colour neg on one page.
Convention says smaller terminal on speaker is neg too, which might help.

I connected up, turned radio on and watched as my speaker pulsed into & not out so swapped the wires over. Job done.

Good link 5,000 + sub woffers on ebay what's all that about.