740il no-start

HI I have a friend with a 740IL which doesn't crank over. he claims to have washed the engine compartment and engine and after that not able to start it. it just clicks like a dead battery. tried attaching jumper pack but to no luck. battery voltage kinda low around 11.84v. with pack still only 12.25v. but that should be enough to crank over. was wondering if anyone came across similar problem. also found letter from repair shop saying to replace head gasket and customer declined over a year ago. am going to manually try to turn crank right now. but anythoughts on sensors or security items to check first would be nice. all fuses look good at this time.

If it clicks, it's not the security