Display shows LOC or LOCK and buttons on the topside control are unresponsive.

Basic unlock: Refer to your specific Marquis spa owner's manual, but common unlock methods include:

• Press and hold the Temp Up and Temp Down buttons together for 3–5 seconds.
• Press and hold the Light button for several seconds.

If still locked:

• Power cycle: Turn the GFCI breaker OFF for 30 seconds, then ON. Some lock modes reset on power cycle.
• Inspect keypad: Check for stuck or damaged buttons, or moisture under the overlay. If buttons feel mushy or always pressed, the topside control may need replacement.