Chosen Solution
I have a Macbook C2D 2.16 GHz laptop. The screen was cracked and doesn’t charge/run of battery, and I wanted to use this as a desktop. I removed the display and rerouted the wifi wires around the dvd drive. Everything works well, but when it turns on, it thinks that the display is open so it uses the external monitor as a second display. When I put it to sleep and wake it up, same thing. I want to know how the macbook recognizes when the display is open vs closed so I can try to make the computer think the diplay is closed all the time ie when it wakes from sleep, it thinks the display is closed and uses the external monitor as the main monitor.
It’s called a Reed Switch. Here are some answers that may help you to understand how it works: What is the reed switch for? Here’s a good reference on it: http://www.ifixit.com/Discuss/thread/384… Here’s a good thread on it, go to the fourth one down: http://forum.notebookreview.com/dell/126… Here’s Apple’s discussion on the problem: http://discussions.apple.com/thread.jspa…
On a 2015 MBPro, 13-inch, the reed switch is just to the left of the Tab key (under the aluminium).
