I have a 2003 acura TL 3.2l V6
And yesterday it wouldnt start. I went to get in, and no lights no clicks. Figure a light must have been left on, and after some difficulty get it to jump. Drive to work, shut off all my lights and fans and turn the car off. Lights come on when i turn the key. But as soon as i turn it all the way, nothing. Everything dead again. No clicks no lights. Get a jump after work, with much difficulty. Get it to start. Dont know what i did, but eventually it jumped. Take it to autozone to get the battery checked, and its 100%. And magically starts on its own. Drive home. This morning, all lights work, everything looks great. As soon as i try to turn the engine over, everything dead. No lights no clicks. Dont know where to look other than starter

 

Check your grounds, they are braided cables in the engine compartment. Also your negative battery cable may need to be replaced.

 

Ok, Im going out now to run down a few more quick things. Going to try and start again, and check connections again

 

 

If the grounds are good and the terminals are clean and tight then it can be a bad ignition switch.
Question, Do you have an aftermarket alarm ?

 

As far as im aware, its all stock. Its got upgraded options. But i dont think anything is after Market. and to top it off, i went out and opened rhe hood. Pretty much just shined a light on it. And magically it started. When i first went out it was dead. Now it magically works. I didnt really even touch anything.

 

Does your alarm go off randomly for no apparent reason?

EDIT: I'm almost certain it's a problem with your battery cables, likely your negative one. Try turning your dome light on or open your door and wiggle them. See if the lights flicker or go out.

 

My alarm has not gone off at all, unless my son has my keys. And im just waiting for my phone to charge a little and ill do that. I found one ground, #4. Need more light to find the rest, ill be looking more and trying what you said in a minute. Ill wiggle everything in a sec and see if lights flicker.

 

No change by wiggling any wires around the battery, the light stays on and the car is still starting. Not loosing all power like before either. I put some force into moving the wires as well, everything was solid. Still cant find the other ground. im thinking its behind something

 

But the battery ground looks good. I feel like the engine ground is hiding where i cant see it from the top/without removing things

 

Id say its the battery then, Remember it was tested when it was working, not when it wasn't. That is if you're certain the grounds are good.
Ever changed the battery ?

 

When i got the car two years ago, the transmission had just been replaced. And then i repaved the battery. Other than that, i replaced the blower motor and had the egr valve cleaned.

 

Check both fuses 41 and 42, I have seen these type of fuses link break and cause intermittent connection, Look for burn spots inside

 

I checked the fuses, and everything looks fine. The cars been running fine today. I took it into a shop and just had them look over it to see if they could see anything. And other than wanting to replace my positive battery cable, they didn't have much to say. There was some green corrosion in the actual cable itself that you could see after removing a bit of take that was on the end. The terminals are fine but i hadn't noticed the cable itself

 

The cables are known for coming apart inside the connectors. I'd follow their advice and replace your battery cables.