Mighty Mule gate opener diagnostics and repair

This is for Mighty Mule MM571W, though they all seem fairly similar. With the power off, I cleaned and dried everything within the arm, ensured all connections were good, and cleaned and greased the hinges and bearings to ensure ease of movement to rule out the easiest problems. After restoring power it still didn’t work, so on to some other diagnostics. Increasing the “Dual Sense Stall Force Setting” (what it’s called in the owners manual) also did not cause it to function any differently. I tested the 12V battery and it tested at 12.9V, so I expected that to be ok. During testing the arm did seem to attempt to function so it didn’t seem to be a safety stop, and the arm seemed to be getting a proper signal as well. At this point I suspected maybe the battery wasn’t putting out enough juice. This video goes over a few of these things, as well as how I tested the bad battery theory by hooking up another 12V battery (and 25A fuse) in parallel to see if more juice was indeed the answer. I ordered a replacement battery for $20 the same day as this testing and upon installation everything has functioned as intended since! I also disassembled the arm again and cleaned the mating surfaces and added some rtv silicone, as well as adding some Teflon tape to the end cap’s threads to inhibit water from entering the arm, as there was some water in it when I first opened it.