2005 s40i car wont start/ no power when key is on

[mooseknuckle]

Drove car to work, went to leave, and made it about one block/ two lights. car felt sluggish and slow, then had no response from pedal. Rolled to the next light and car died. used jump box and got it running, but barley. made it to autozone, and it died in the parking spot. seemed to me like a dead alternator, so I bought a battery to make it home. (Note my headlights never turn off, asked dealer for a software update to fix that, and they told me I don't need one, that I had to deal with it. one reason I wont go to the Volvo dealer in my area.) so on my way home was loosing power steering when turning, like it has been doing for about a week. got car home, barley, and it died. checked volts at battery and were 12.5v tried to jump start to make sure it had enough power. and still clicked like a dead battery. then I got an immoblizer on the dash screen, and when you turn to pos 2 looses all power. left battery unplugged all night, checked this morning, and had 11.57v. hooked up terminals and had the same volts, checked with earth wire on strut tower, and had same volts, checked main fuses(the black bolt on ones in engine fuse box) and had same volts through out. checked starter solenoid with key off and had .2v at power wire. turned key on and all lights dimmed and turned off, heard clicking from in car fuse panel. checked battery again, only had 3.85v. turned key off, unplugged battery, and checked again, had 11.65v. I am thinking ignition switch solenoid/ aka starter control valve? please if anyone has had this issue, or can help I really need this car. thank you for reading this long post, just trying to give as much info as possible. thank you

[ejbj]

Hi, i had a similar experience but just for an instant. i had replaced the power steering fluid and some got on the serpentine belt and the engine started acting and got warning lights. Stop safely... steering angle error... dstc error.... Only missing was the "you are sc****d and in for a nice tab"
I used some dish detergent and plenty water, belt stopped slipping.
It might be a sketchy alternator that does not keep up with the cars drain, or a slipping belt.
Check your belt and test voltage as connect loads as Seat heaters, lights window regulators...

Best luck.