Chosen Solution

I have a MacBook Pro 15" Unibody Late 2008 and Early 2009 with a dead hard drive and no battery. It starts up fine with an Apple OS disc but the fans are on high and the backlight is out. I can barely see the Apple logo in the middle of the screen and hear the cd chiming away. Any ideas? No damage physically to the Macbook. First thing I did was reset the SMC which got it turning on. Took me a few tries to get it to turn on, than I zapped the pram, now the above is my problem. I did remove the back cover and the motherboard looks good. I’m stumped, especially since the fans keep going on high. Thanks.

Hook it up to an external monitor to narrow down your diagnostic search. MacBook Pro 15" Unibody Late 2008 and Early 2009 Display Assembly Replacement

The system is designed to have a battery installed. Within the battery pack is a thermal sensor which is part of SMC services if its not getting its signal the system goes into fail-safe mode pushing the fan to the max as it assumes the system needs to be cooled. Lets install this app TG Pro you’ll need to get the older version that works with the Mac OS-X you are using on your drive. Post an email to Matt asking for it, tell him you are having a problem and the folks here on IFIXIT recommended using it (support@tunabelly.com). It will allow you to see the thermal sensors and the fans within your system. Take a snapshot of the main window so we can see all of the sensors maybe we can spot whats not working properly here if it’s not the missing battery.