2004 Mustang GT, bought it new... Over the lifetime of the car, there have been several times when I go to start it up and all I get is the dash lights lighting up, but no cranking whatsoever. No click from the starter, no sound whatsoever. Seems similar to if the battery was completely dead, but the battery is fine (dash lights all light up as expected). It's as if I turned the key only to the ACC setting, although I *KNOW* I turned it all the way (I know what that sounds like but trust me!) Usually, after trying to crank it a couple times, I'll take the key out and try again and it will start right up with no problems. Any idea what this could be?

 

Sounds like something is loose in the steering comlumn...

 

it has to do with the factory security system on the car i think, when the car thinks its being stolen everything will come on and work however the starter will not engage to start the car. this is why it wont turn over. so yes its probably something in the steering column that is causing this problem.

 

I had that prom.. And it was the alternator try replacing it

 

The PATS used in all 1994 through 2004 Mustang does not have an immobiliser (starter interlock), that was introduced in 2005. The OP's 2004 uses the PATS type C system, as did all '99 through '04 models--the engine will crank but not start if PATS has activated (PATS disables the fuel pump and injectors). Type C has been proven to be extremely reliable.

One question for the OP, when you try to start the engine, and it won't start,
do the gauges "sweep" across their range when you stop trying to crank, or when the key is next turned on? If they do then the battery is bad or not fully charged.

If they do not sweep then make a few voltage tests before blindly swapping out parts:

• Check the battery terminal connectors, make sure they are clean and tight;
  
  
• Check the voltage across the negative and positive battery connectors, NOT the battery posts, while cranking (or trying to crank) the engine--it should be 10.5V or better, if not the battery is likely bad; have it load tested at an auto-electric shop--NOT a FLAPS--they will also be able to test/verify the generator's operation;
  
  If the voltage does not change at all, or changes just a small bit (<0.25V) then the starter relay is not being activated--this could be the relay itself or an ignition switch issue. The relay is located in the Battery Junction Box under the hood, you should be able to here it click when the key is turned to START--if it does not then it is defection or not getting power.
  
  
• When it starts, with the engine idling:
  
  
  • Measure the voltage between the battery negative post and the negative connector--it should be near 0.0V, if not the negative connector is dirty or improperly connected;
    
    
  • Measure the voltage between the battery positive post and the positive connector--it should be near 0.0V, if not the positive connector is dirty or improperly connected;
    
    
  • Measure the voltage from the generator body to the negative battery post, it should be near 0.0V--if not there is a bad ground path between the generator body and the battery;
    
    
  • Measure the voltage from the generator output terminal to the battery positive post, it should be near 0.0V--if not there is a bad connection between the generator output and the battery;

These simple tests will either find the problem, or rule out the battery, connections, and wiring.