Start with the checks Bosch gives owners: confirm the refrigerator has power, check the temperature setting and move containers away from the interior vents. Those observations come before deciding that a compressor has failed. Bosch cooling troubleshooting.
A lit display can still mean cooling is off
Demo mode is one possibility, but the procedure depends on the refrigerator. Bosch’s manual for B36IT905NP, B36BT935NS, B30IB905SP and B30BB935SS lists a powered display with no cooling under its Demo mode troubleshooting entry. Its Settings section explains that mode. On those four models the manual says the Demo mode item shows in the settings menu for 3 minutes after the appliance is switched on. To turn demo mode off later, switch the refrigerator off and back on, then change the setting while it is displayed. Other Bosch models may use a different procedure, so match the E-Nr first. Bosch manual, Settings and Faults sections.
Find the E-Nr on the appliance label and match it to the manual before changing service settings. Tell us what the screen actually shows; a photo is more useful than a guessed error name.
Keep the owner checks accessible
Look for food blocking a vent or preventing a door from closing. Note whether both compartments are warm or only one. Leave machinery covers in place, and use the cleaning directions for your model rather than assuming its coils are accessible from the front.
If power and settings are correct but the cabinet remains warm, arrange service. Bosch directs owners to seek help when its basic checks do not restore cooling. Past that point it takes a meter and an open panel to tell a fan from a control from the sealed system. Bosch owner support.
For Bosch refrigerator service, use our refrigeration repair page or book a diagnostic visit. Bring the E-Nr and your observations. The visit is $99 with credit toward an approved repair; the repair itself is quoted after diagnosis.