Chosen Solution
My MacBook Pro is having sleep issues that seem related to the hall sensor (often referred to as the reed switch), and I would like to know if I can solve the problem by physically disconnecting the sensor. [A detailed description of the symptoms is below.] I’d be perfectly happy if I could simply sleep / wake the machine “manually,” with the clamshell open, and closing or opening the clamshell as appropriate without affecting the machine’s sleep state. Is physically disconnecting the hall sensor possible? If so, would it accomplish this? Symptoms: The machine will suddenly go to sleep while being used (and with the clamshell open). That is the big problem. Also: if I close the clamshell with the machine awake, it goes to sleep. Then after a few seconds it seems to wake up. The sleep indicator light starts blinking rapidly (rather than pulsing slowly). If I sleep the machine with the clamshell open (e.g. by selecting “sleep” form the Apple menu in the Finder), it will wake up after I close the clamshell. Diagnostics / system info: The main tests in Apple Hardware Test and Apple Service Diagnostics (both OS and EFI) show no issues, aside from a press of the battery indicator light button not being registered by the SMC. One of the interactive tests in ASD intermittently registers a problem with sleep/wake and the clamshell. I have an SSD in the main drive bay, and I replaced the optical drive with the hard drive that came with the machine (using OWC’s “data doubler” bracket). This problem did not crop up until many months after I replaced the optical drive with the hard drive.
I suspect you have two issues here: The first - When your system goes into sleep mode on its own its likely a SMC issue. Lets try resetting the SMC. Follow this Apple TN: Intel-based Macs: Resetting the System Management Controller (SMC). In addition you need to check your battery. I would recommend this gem of an app: coconutBattery. Take a snapshot of what it reports and post it here for us to see. The second: Sleep wake issues like you describe are often caused by background running processes. Try this using an external hard drive which had a clean OS on it (nothing else) see if your system reacts any different. If it does you have some work to isolate out whats waking up your system.
