I have a 2007 Crown Victoria Police Interceptor that will randomly not start. When it doesn't start with the key, I am able to put a booster on the battery and it fires right up. I got the battery (which is 2 1/2 years old) tested and it is fine. When I took it to a mechanic, he said that both my dash and my key fob are after-market, so he thought it might be the security system that is causing the problem and that I needed the fob to be in the car for it to start. But after that, I was able to start it a few times with the key even when the fob was not in the vehicle. Now it is not starting again. When I turn the key, there is only clicking. Everything else works fine -- all the dash lights work, etc. Any thoughts?

 

I would have the battery tested, remove and clean all electrical connections. That includes at the battery, ground point on the engine and all the way down to the starter. Verify the charging system is charging the battery. Still having issues, gently tap the starter with a hammer, broomstick or whatever you have when you cannot crank the engine. The clicking you hear is the starter's relay which tells you that it is receiving energy so I wouldn't suspect the security system. I do remember a TSB mentioning something regarding connection problems at the starter.

 

Thanks for the suggestion. I'll try it out.