Audio Systems: Installing New Radio, fiat bertone x1 9, fiat bertone

Question
hello, i am trying to install a new cd am/fm radio in our 1982 Fiat Bertone X1/9. I am installing a Sony CDX 4180. i am having trouble getting it to work. i think i have found the live wire in the car because it gave off a spark, this is a black wire. i also think i found the power wire for ignition turn on, it is blue. i had these hooked up and nothing happened. i had the red wire from the sony hooked to the blue of the car and the yellow from the sony to the black of the car. would this be right or would they need to be switched around? i did have the yellow from the sony hooked to the blue of the car and heard the cd device do something. i have done this since then and nothing happened. not sure if you can help. thanks!!

Answer
go buy a digital multimeter before you blow something up! Measure each wire with the key on, off, and accessory. The memory lead will have power always, the accessory lead will have power except in off and crank. The ground wire is an important one, make sure it's ground! The illumination wire can be mistaken for ground, check it for voltage while on.