I tried to replace my stock am/fm cassette radio and blew the fuse. Now it just wont play. Do I have to rewire the speakers? Any info would be helpful I am tired of singing "Henry the 8th" (second verse same as the first). I left the harness on the side of the road in CA. Will have to buy new.

 

I replaced the stereo in our 940 a few years back.
I got my stereo from www.crutchfield.com and they are really great at giving you everything you need to match a new stereo to whatever car you have. In my kit came some trim to finish off the installation, as well as a wiring harness, with instructions on how to mate it with the in car harness (a little time of soldering, on the bench, and it was done). I did not have to rewire speakers (although the 2 on top of the dash are in op now- just the 4 door speakers (can't tell the difference))- but that is just because the stereo/cd I bought did not have outputs for them.
Most new stereo's have a built in Amp, so you bypass the Volvo Factory one, but that is easy and taken care of in the harness building step.
Go to the website, or give them a call, tell them what you have and what you want to replace and I think they can get you squared away pretty easily. From what I remember the 'bits & pieces' were well priced.
Koos