Subzero 650 light won't stay on when door shut

This doesn't sound like a thermocouple issue, it sounds like you don't have enough fresh air in the unit, is something plugged somwhere?

Hi there,
Is it possible to elaborate a bit? Is it sticking? Jamming? Slamming? Not staying closed or sealed? Most of the time problems arise from damage to the white rubber seal (subzero's are specially fitted to ensure a stellar seal). Check along the entire rectangle surface for any cuts or problem areas.

Good luck!

There is defrost heater which comes on in defrost cycle. defrost heater stays on certain time(lets say 15 min), but lets think it came on to defrost and melted all ice of the coils during 5 min, but we still have 10 more min design for heater to stay on. if heater will stay another 10 min it will warm up your stuff in the freezer, so everything will start to melt. to get around this, all freezers have limit thermostat(defrost thermostat), when that thermostat feels heat from heater, it will shut power off to the heater, so it still in defrost cycle, but heater will be off for another 10 min. When that thermostat get stuck in closed position(does not shut power to the heater when all ice melted out), you will have defrost overheat. so most likely that defrost thermostat needs to be replaced. here is the video how i replaced it on subzero pro series.

Hate to say it, but that could be anything. I would start by emptying the fridge, shelves, drawers and all and seeing if it closes. 9 times out of 10 I see something obstructing it. If that doesn't doo it, then the door closer may be bad. They have 2 styles on this unit depending on age. either 2 white plastic cams that can break and "squish" out from between the 2 halves of the bottom hinge, or a closer arm that has lost it's tension and needs to be replaced. That would be rare, but it can happen. I have also seen one instance where the pair of switches at the bottom of the door have gotten so hard to push in, that they hold the door open. push those in by hand and make sure they don't resist too much. The other thing that can cause this is a sagging door. the lower hinge can bend or sag and the whole door droops then doesn't allow it to line up correctly with the box. look for signs of that too. Hope this helps.

it does not shut because you did lot of minuts and it is frozen

If the door will not stay closed it is the spring inside door, or the small plastic piece that holds the spring which is attached to the $80.00 piece called outer door.
To fix it, it is EASY and you do not have to even take the inside cover all the way off. Just remove the three sides of cover by gently slipping a plastic putty knife around rim to release the clips. Then attach the spring to the small hole below where the plastic piece used to be, which is located in the metal on the glass frame piece, use tweezers, hold the other end of spring as you place spring onto plastic door latch and set into place!
Snap the inside cover back on and YAY! FINI!

Here is a helpful video

Hi!! you have a seal system problem.A leak in the evaporator..

Your evaporator needs replacing. covered under 12 yr. warranty parts only.

Just a guess, but I would check the gasket on the door. They can go bad or get distorted and bunch up and cause the door to bind and not close properly. Also check that the fridge is leveled properly. Will the door close if pushed? Will it stay closed?