I have a 2005 crossfire with 32,000 actual miles. I leave it in the garage during the summer when I head back to
Tennessee. When we arrived last week the car started with no problem. After several days the car would not start and had a new battery installed. after several days of driving, when out this morning and could not un lock the car with the key fob. unlocked the car with the key, got in put the key in the ignition turn the key and nothing . none of the lights work nothing works. Anyone got any ideas what the problem could be? any help or info would be appreciated

 

When locked by fob, have to unlock by fob, using the key will set the security alarm off, but if a new battery just installed and no lights or anything works, check the battery for connections and voltage, if lights work and will not start and acts like the battery in fob is dead, unhook the negative terminal and let it sit, or go ahead and remove both and let it sit awhile, usually 5 to 15 minutes is long enough but depends on how much in the system needs to drain and reset.
go longer to be safe.

 

Measure voltage across battery terminals, if OK ( 11.6 - 12.6 volts ), then measure from + terminal to engine block.
If that is not the same, or very close to the same, then you have a battery ground cable issue.