You don't need the wiring diagram.
If there is a fuse on the block labeled radio, run a wire to the power wire for your new radio. If there is not one labeled, take a test light and find a circuit that is hot only with the key on. That will be your power to the radio. Then take the test light and find a circuit that is hot all the time. This will be the constant power line to the radio. This will save your clock and presets. The only other wire you need is to a ground. You can just find a place to take a sheet metal screw and screw into the firewall.
From my experience, the power wire is red, the constant power (always hot) is usually orange, and the ground is black..
If there is a fuse on the block labeled radio, run a wire to the power wire for your new radio. If there is not one labeled, take a test light and find a circuit that is hot only with the key on. That will be your power to the radio. Then take the test light and find a circuit that is hot all the time. This will be the constant power line to the radio. This will save your clock and presets. The only other wire you need is to a ground. You can just find a place to take a sheet metal screw and screw into the firewall.
From my experience, the power wire is red, the constant power (always hot) is usually orange, and the ground is black..