What Does the Door Switch Control?

Where it sits

In the opening the door shuts into rather than on the door itself — low on the pillar at the hinge side, or tucked under the top edge. Each door on a two-door built-in has one.

It reports a position and nothing more. Sub-Zero lights a Designer Series interior overhead, under every shelf and inside each crisper drawer, and all of it goes dark on the same signal that says the door has come home. The alarm listens to that signal too, which is how one small component produces two complaints that sound unrelated.

How it fails

Three ways, and only one is the switch’s own doing. It loses travel: thousands of closings flatten a moving face, or spilled juice dries around it, and it stops changing state where it used to — so the lamp burns behind a shut door, warming the compartment it exists to light. It is right while the door is wrong: a cabinet that will not draw fully home leaves the switch reporting what it finds, and taping over the sound throws away the only thing telling you about the gap. Or it drifts: a front that has settled, or joinery reset after a Toluca Lake kitchen was refaced, moves the face it meets by a fraction, and a fraction is all the travel there is.

What replacing it involves

The door gets read first: whether the front closes square and holds contact all the way round, because this component is cheap to blame and often innocent. Where the switch itself has gone, it comes out with the cabinet standing where the kitchen put it and a genuine Sub-Zero part goes back, custom joinery untouched. Then the door is closed on it several times while lamp and alarm are both watched.