Changing a stereo in a car can be very frustrating if you do not get the wires straight. If your positive lead is connected to the speaker, you will not be getting any power to the stereo. For this reason, manufacturers have come up with a color coding for the wires so that you can connect all the wires correctly. Jensen stereos have a wiring color scheme that is similer to other manufacturers, but you should always check the color schemes of the car and the stereo to make sure they are the same.
Locate the antenna. This is a thick black wire inside the dash with a connector that looks almost like a coax connector. Plug it into the jack marked "antenna in" on the Jensen stereo.
Plug the harnness with the blue, red, yellow and black wires into the stereo in the slot in which it will fit. This is the power harness. The blue wire goes to the power antenna, the red wire powers the accessory side of the fuse block, the black wire is the ground and the yellow wire is your live, positive lead.
Connect the speakers. Look for markings on the wires coming from the car to see which wires go to which speakers. If this isn't known, pick speaker wires and plug them into the speaker wire slots on the stereo until you get them in the right place. Plug positive into positive, and negative into negative. Usually, the negative side has a silver line on it.
Connect any other accessories into the connector ports on the stereo. These include amps or, if your stereo accepts them, back-seat screens. Each connector port will be marked with what it is for.
