Originally Posted by TheQ
Cavie, OK I understand the 12V, 3 terminals but not the last part. Can you clarify? Thx.
An unlighted switch is just 2 wires in this application (SPST). Positive wire coming in, and wire going to heating pad.
A lighted switch needs 3 wires - adding a negative/ground to complete the circuit for LED...
If a negative wire isnít present, would need to run one... but assuming your switches are part of the control panel, Iím sure there is a negative/ground wire you can use.