Sub-Zero Classic BI Code 90-L-38: Interior lighting output error

What 90-L-38 means

On Classic Built-In refrigerators with electronic control, such as the BI-36UFD/S, 90-L-38 means the control board's FET power output for the lighting reported an error. The lights inside the cabinet may stay off, flicker or work only part of the time. Cooling is not directly involved, but the board flags the output so the problem gets attention before the board itself suffers.

Common causes of 90-L-38

Failed lighting output on the main board
Shorted light fixture or LED module
Damaged wiring to the lights

✓ One safe check you can try

1. Note 90-L-38. 2. Check whether the lights come on when each door opens. 3. Interrupt power at the breaker for a couple of minutes and bring it back. 4. See whether the lights and display return to normal. 5. Contact us if the code comes back or the lights stay dark.

! Why to stop there

Light fixtures and wiring sit behind interior trim.
A shorted light can damage a new board.
Board outputs are tested with power on.

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

23Sub-Zero 600, 700 and 648PRO Code 23: Defrost overheat with no feedback 50Sub-Zero 600 and 700 Series Code 50: Refrigerator compressor running too long 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

90-L-3890-L-38 questions

Is my refrigerator safe to use with 90-L-38?

Yes. This code concerns the lighting output only. Cooling continues normally, though finding things in a dark cabinet is inconvenient and the door may stay open longer than usual.

Is it the light or the board?

It can be either. A shorted LED module can pull the output down, or the output on the board can fail by itself. We test the lights and the output separately.

What will it cost?

We confirm the cause, then give you a written price for the light, wiring or board before anything is replaced. Our labor is backed by a 30-day warranty.