I bought this harness to replace the factory harness that was cut when the factory stereo was stolen. (Who wants factory stereos?!?!) I used this on a 1995 Saturn SL1. The harness colors do not match the factory colors 100%, so I had to look up the factory wire colors on the internet. To do this right, you should solder the wires and heat shrink the solder joint. (That's why I gave it 4 stars for the Easy to install.) I don't suggest using 3M Scotchlocs. Don't be lazy. Do it right.The harness has a lot of wires. When I used it in a 1995 Saturn SL1, there were several wires on the harness that were unused. The harness is used for several vehicles, so it is likely that some wires won't be used.Specifically, with the 1995 Saturn SL1, there were a couple wires on the factory harness that were the same color. You'll need to use a mulitimeter to figure out which wire is a speaker wire or a illumination wire (both brown.) I could have just wired the aftermarket stereo harness to the factory wiring harness, but I wanted to be able to remove the aftermarket radio and move it to a new vehicle without cutting the harness off the factory wires.