Why doesn't car speaker work?

Wiring stereo; wired one speaker, worked. Wired second speaker, first speaker doesnt work. Help!!?

• I'm wiring an aftermarket stereo which I didn't have the original dash harness. I managed to find some color codes and started wiring. Finally figured out the ignition wire, still no clue about the constant 12V, which Ill figure out later. Anyways, I wired one speaker that worked but sounded very weak. I wired a second speaker which worked too, but only to find out the first speaker wasn't playing. Can anyone help? Or know the reason this happened. I'm not too positive if I maybe switched the wires between + and - or what the reason is.

• Answer:

  Hi yes i know what you have done. this is why you really need the units wiring diagram. some stereos use ground as the return path for the speaker systems. what you did was to use the + wire from both channels as it would work its what Linsey Hood did when he designed the first quad systems . and why you need the wiring diagram it should be available on the internet some where do some searches .