I know similar questions about MOSFETs not turning off have been asked so many times, but I've tried everything I've read, without luck.
I use a N-ch MOSFET (IRLML2502TRPBF) for both reverse polarity protection and as a power switch (through a slide switch).
See schematics (I should have added a gate resistor, but forgot). The rest of the circuit is pulling about 215mA from this switch (both with the MOSFET in place, and with a bridge between pin 2 and 3). It should be powered with 4x AA batteries, but for testing I use a power supply set to 6V and limited to 300mA.
I've tried with pull-downs from 1M, 100k, 47k, 10k and at the last attempt 1k. The only thing happening is the draw drops to about 170mA when I turn "off" the slide switch, then back on it draws the normal 215mA.
I measure 5.9V on gate when slide switch is on, 0V when off (both relative to GND / source). If I measure relative to REV_POL_GND (drain), I see 5.9V when on, 0.65V when off. Just for the heck of it, I then tried to place the pull resistor between gate and drain, no luck there either.
Did I miss anything?