I have a Prusa i3 with a RAMPS 1.4 board. I think I have two problems that may be related, but I'm hoping I can work around them.
Firstly, I'm pretty sure the FET running my heated bed has failed, so I remapped my heat bed to the D9 output in pins.h. That was working okay, but the fuse was overheating from powering the hot end and the heat bed together.
So, I wired the heated bed through a relay to reduce the load on the RAMPS board, but then it was making a clicking noise.
So then I went to go disable PID control in configuration.h by commenting out
//#define PIDTEMPBED
//#define BED_LIMIT_SWITCHING
but that isn't working, the relay is still switching rapidly.
Am I missing some other setting? Is disabling the PIDTEMPBED setting not working because I'm using D9 instead of D8? even though I've remapped that pin?