Dad's 01 v6 won't start. Just clicking at me!

Either the battery cannot take a charge or there's a large parasitic draw. 11.XX volts is severerly discharged.
 
same problem

I have a 2004 v6 mustang and it won't start. When I turn the key all I hear is a clicking sound. The battery died last week so I replaced it. Last night I tried to start my car and it wouldn't start. The radio and dome lights all turn on but the car wouldn't turn over. I have replaced the battery and now the alternator. When I put the key in the ignition and turn it (not all the way) the radio and all lights come on. Once I turn the key all the way I hear a clicking noise and everything goes dead. I'm at a loss as to what else I am needing to do. Any help would be GREATLY appreciated!!!!!!!!!!
 
I have a 2004 v6 mustang and it won't start. When I turn the key all I hear is a clicking sound. The battery died last week so I replaced it. Last night I tried to start my car and it wouldn't start. The radio and dome lights all turn on but the car wouldn't turn over. I have replaced the battery and now the alternator. When I put the key in the ignition and turn it (not all the way) the radio and all lights come on. Once I turn the key all the way I hear a clicking noise and everything goes dead. I'm at a loss as to what else I am needing to do. Any help would be GREATLY appreciated!!!!!!!!!!

Welcome to the boards. :)

Are the power-cable connections clean? This would include the connection on the side of the underhood fusebox and the motor ground.

Do the headlights come on strong and stay strong over a 30 second period?

Have you checked battery voltage with a DMM? It should be over 12.6V static and not drop under 10 V while cranking.

Have you tried using a jumper battery to see if it will start?