Thought alternator might not be working, checked voltage while running it was good. Removed battery cables to clean, put back on and wont start now. Battery is fine but wont turn over and radio says code. WHAT HAVE I DONE???

 

Well the stereo saying "CODE" is because you need to enter the security code for the stereo.
As for it not starting now, eitheryou have a lose connecton with the battery cabel, or the battery is toast.

 

Why did you think the alt. was bad? Did the voltage increace with the rpms? The battery can look charged with a meter but not be good enough to start the engine. I use one of these for checking batterys. Every garage needs one. http://www.minnkotamotors.com/produc....asp?pg=mkbm1d

Willie