Sub-Zero Classic BI Code 15-L-00: main lights relay open

What 15-L-00 means

Classic Built-In refrigerators like the BI-36UFD/S use 15-L-00 to report a lighting relay stuck open. This relay powers the main interior lights. When it will not close, the lights stay dark when you open the door, even with good bulbs or lamps. Cooling, ice and water are on other circuits, so the refrigerator keeps working as usual. The code and dark compartments are the only signs.

Common causes of 15-L-00

A main lights relay on the board that will not close
A loose plug at the lighting circuit
A control board that needs repair

✓ One safe check you can try

1. Open and close the door to make sure the door switch is being pressed. 2. Reset the breaker once. 3. Use a flashlight or a battery puck light inside the cabinet in the meantime. 4. If 15-L-00 stays, schedule a visit at a convenient time.

! Why to stop there

The relay is on the control board, which carries line voltage
Lights can run at line voltage on these models
Replacing lamps will not help when the relay sends no power

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Refrigerator codes

41Sub-Zero 648PRO Code 41: Zone compressor or wiring problem 81Sub-Zero 700-2 Code 81: Variable-Speed compressor fails to start 82Sub-Zero 700-2 Code 82: VS compressor controller needs replacement 88Sub-Zero 700TF Code 88: Board and compressor controller not talking 80Sub-Zero 700TF Code 80: No inverter feedback after a board change ddSub-Zero 600 and 700 Series Display dd: Diagnostics switched off deSub-Zero 600 and 700 Series Display de: Diagnostics enabled 23Sub-Zero 600, 700 and 648PRO Code 23: Defrost overheat with no feedback

15-L-0015-L-00 questions

Is 15-L-00 a bulb problem?

No. The code points to the relay that powers the lights, not the lamps. New bulbs would stay dark the same way until the relay side is repaired.

Is it safe to keep using the refrigerator?

Yes. Lighting is on its own relay, separate from cooling, so food stays cold with the lights out. You can plan the visit around your schedule and keep a flashlight handy.

What does the repair involve?

We confirm the relay is stuck open, check the lighting plug, and repair the board side. You approve a written price first, and labor has a 30-day workmanship warranty.