[Jaahas]

As the title says my 2005 CTS has had this problem for some time now that it doesn't even try to start if i don't have the battery charger connected overnight after it starts up just fine, well sounds like a bad battery right? But even new battery didn't solve the problem and i ran a battery test which indicated that the battery was good.
Well then the weird part is that after an about 3 hour drive during which the car worked fine, i shut it off, and tried to start it and, nothing.
So what would be the problem? I've been worried about the ECM going bad and since i live in Finland, a new ECM from US is gonna take forever and the nearest Cadillac (or GM in general) dealer is in Germany so that's a no

 

[synct]

It sounds like you either you have bad alternator or a parasitic battery drain. I’ve had this with my BMW. Some circuit is open that’s causing an electric power drain. First, test your alternator. If it’s good, you have to take a voltmeter and look for a draw on each fuse.

 

[RyanY]

A common problem is the small slide switch in front of the sunroof. If that switch is all the way forward, the battery will drain overnight. If the switch is back just a little, no more battery drain. Hopefully your problem is this easy to solve!

 

[Jaahas]

It sounds like you either you have bad alternator or a parasitic battery drain. I’ve had this with my BMW. Some circuit is open that’s causing an electric power drain. First, test your alternator. If it’s good, you have to take a voltmeter and look for a draw on each fuse.

Ah yes i forgot to mention that i did find a parasitic draw from LT Park fuse about 2.5 amps, but the thing is that car won't start right after a long drive and the DIC says that the battery voltage is 13. Something, so i've been suspecting the alternator too

 

[Jaahas]

This one is new, i'll see if that fixes the problem

 

[Jaahas]

A common problem is the small slide switch in front of the sunroof. If that switch is all the way forward, the battery will drain overnight. If the switch is back just a little, no more battery drain. Hopefully your problem is this easy to solve!

So got back from a short trip and checked that, the interior light switch is set back a notch, like i thought so that's not the problem

 

[lambert]

Ah yes i forgot to mention that i did find a parasitic draw from LT Park fuse about 2.5 amps, but the thing is that car won't start right after a long drive and the DIC says that the battery voltage is 13. Something, so i've been suspecting the alternator too2 says bad diode i reckon why the display is showing batt, volyage good and also bad..yes ..glad im not a blonde on top of this prob. im currently in process of alt. change and yes ittza beoche!

r&r alt. izza beoche lol! my obd