Absolutely the toggle switch. Depending on which pole fails you can get all kinds of weird issues. Losing P24C can cause various selector lockups, P24GS causes hall call lights to go out after the call is latched, & loosing AC1SW drops out the power supply but that seems to be more rare. Maybe because the AC voltage keeps the contact in better condition. I keep them on the van and replace them pretty often and always when replacing a power supply.
