Old battery was putting out about 7 volts, enough for lights to come on but dim. New battery putting out 12V but have nothing. doesn't click when start. Everything is dead, i.e. lights, horn etc.....
12v is actually a bit low. 12.1V is a 50% charge. Put a charger on it for a half day Just check it when you do get it running and needs to be 13.5 to 14.5V Even when not running. Check your cables, all four ends, 2 on Red+ cable, battery and starter solenoid, ground, battery and follow it wherever it leads, probably block and make sure is clean and tight.
Looking for a Used Monte Carlo in your area?
CarGurus has 1,402 nationwide Monte Carlo listings starting at $2,588.
Search Chevrolet Monte Carlo Questions
Chevrolet Monte Carlo Experts