2000 3.5L sometimes won't start

I have a 2000 Intrigue with the 3.5L engine. The car sometimes won't start, this has been going on for about a year and a half. The power comes on, but it just won't crank. 15 minutes later it will start. The security light will come on when I'm driving once and a while, then a few days later it won't start. When I go to start the car, the security light is not on though, just the service engine light. What needs to be replaced to fix this?

The key is that your security light has come on at times. That light is normally associated with issues to the ignition switch. Having gone through my own ordeal with a funky ignition switch very recently, I had similar symptoms.

As long as you don't have the "service engine soon" light on, I would start with the ignition switch.

I think dtown means that unless the SES light is on when the car is running you should start with the ignition switch, which I would be inclined to agree with.

Its normal when the key is in the ON position for the SES light to be on, so its not throwing a code, its just staying on.

Search for ignition switch removal if youre interested in trying to clean it, but it might not help much in your case. The security component is inside the switch, so cleaning the external connections might not help much.

Change the battery cable ends first. I went through the replacing the ignition switch exercise..only to still have the problem reappear. Though I had THROUGHLY cleaned and brushed the OEM cable ends. The problem only went away after I lopped off both OEM cables and replaced with $2 terminal ends. I also had done the same procedure on a friends 99 Grand Prix...again it fixed her intermittent no start which was identical to mine. Good Luck

Change the battery cable ends first. I went through the replacing the ignition switch exercise..only to still have the problem reappear. Though I had THROUGHLY cleaned and brushed the OEM cable ends. The problem only went away after I lopped off both OEM cables and replaced with $2 terminal ends. I also had done the same procedure on a friends 99 Grand Prix...again it fixed her intermittent no start which was identical to mine. Good Luck

I agree, its strange but sometimes its extremely hard to get a good reliable battery connection....i've heard some wise mechanics mention about changing out the old original battery and having constant trouble with the terminals...many of them will replace the terminals at the same time as the battery for this reason. oxidation/corrosion is alot worse with the newer, cheaper materials battery posts are made of....so when you replace good quality terminals with newer,cheaper ones...similar materials wont corrode and will make a better connection.

I just thought of another thing that was occuring that led to the ignition switch diagnosis. Even though the car would not start and in most cases would not even make a sound, the radio and HVAC would still come on which told me the battery was not the issue. Plus I had my car stall a few times while driving (car was downshifting). And a couple of times the "security" light came on which confirmed the issue was in the ignition.