Volvo Repair: stereo, 9 volt, test light

Question
I was wondering if there was a way for me to find out what wire was what. im trying to install a new stereo in my 1987 740 GLE Volvo and so i had to get a new wiring harness. is there a site that could tell me or perhaps maybe you know?

Answer
Heather, there is no site but that harness is pretty simple. You need a test light to check for power and a 9 volt battery to figure out which wires are for what speakers.  Red is usually power, yellow or green is for memory. black is for ground and the rest are usually for the speakers.  Roger