I have a 2006 Cadillac STS V6. Aside from having to remove the front bumper to replace the headlights, it's been a pretty decent car, even at the high price GM asks for it. I replaced the battery in it Sept 2015 with a $200, 3yr battery. About 4 months ago (almost a year to the date of replacement) it wouldn't start. It had sat about 2 weeks & I did leave a GPS plugged up, so I assumed it was something I did.

I took it back to where I bought the battery and they tested the battery. The battery is good & he stated "something is draining the battery". Now, it won't start if it sits more than 20 minutes. Cadillac dealership wants $180 to "find" what the problem is & if it's the computer, another $1,000 to fix it. I am seeing this problem a lot across the internet. If it's a widespread problem, why isn't there a recall? Why doesn't GM put as much into the design & sustainability in the cars that they ask us to pay astronomical prices for?

My problem started on or about 25 March 2013, my vehicle had been sitting for about a week because I was ill. I went out to start my car so I might get to an appointment, and all I got was a click. I thought I might have left something on after the last trip I made. So I called and got a jump from my son. Vehicle turned over and away I went. When I came out from my appointment. I pressed the vehicle start button and lights flashed and I heard a click and then nothing. I tried it again and held button in this time and the car started.

I went immediately to an Auto Zone parts store and had them check my battery and alternator. The load tested both and both tested good. I left and went home parked my car and left it overnight. The Next day I attempted to start the car and I got the same sound as I did the day before, just a click. SO I drove the car to a dealership ( Dave Gill Chevrolet, Columbus OH ) and directed them to test battery and replace after test complete. I waited for 2 hours and then they came and got me. They told me the battery and alternator were both good and that I should drive the vehicle around for about an hour to fully charge battery then I should be fine. They charged me for the test and sent me away.

I drove the vehicle like the dealership suggested for an hour and returned home and parked it. Then two days later I went out to drive the car and it wouldn't start again, so I got a jump start and took the car to a shop in Columbus that specializes in auto electrical systems. They diagnosed the vehicle and told me they couldn't fix it there, that a Cadillac Dealer would have to perform the fix. They said the problem was the ignition switch wasn't shutting off after the engine shut down causing the battery to drain. The ECU had to be re-programmed and the ignition switch repaired or replaced. I haven't done this yet but will take car in tomorrow. Hopefully this will be the fix.