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Barry G.
Barry G., Home Appliance Technician
Category: Appliance
Satisfied Customers: 6823
Experience:  27 years in home appliance repair. EPA refrigerant transition and recovery certification type I & II.
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my sub zero 700 series is not cooling I turned it off for a

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my sub zero 700 series is not cooling I turned it off for a few hours and turn it back on trying to reset it but it still is not working I got a 55 on the LED display and last time a tech came out he said something about a defrost switch may not be working right but he got it going again. Any ideas
Thanks for counting on us to help with your appliance problem. My name is XXXXX XXXXX I look forward to helping you! How long has it been turned back on? Is it making any noises at all or is it totally silent?
Customer: replied 4 years ago.

Hi Kelly I turned it back on about 15 mins ago. When is was adjusting the temp it turned off. does not sound likes its running but the lights come on when I open the door

Okay, thank you! The unit has likely gone into a defrost cycle but will come out in about 20-30 minutes. That is normal and likely will not require any service. Allow it to sit for at least 30 minutes after it shut off and see if it comes back on. Please do not rate until it does and if it does not, simply reply back to me and we can continue. Thank you!
Customer: replied 4 years ago.

Thanks How do I get back to you

You can just leave this window open or use a link that has been sent to your email.
Customer: replied 4 years ago.

It has not come on yet. Should it be automatic or do I need to do something?

It should be automatic. Do you hear any fans or anything?
Customer: replied 4 years ago.

No and I have the plate at the bottom off where there is an on off switch which is the one I turned off a few hrs ago and turned back on about an 1hr ago

Okay, are you comfortable with some pretty involved disassembly and working with delicate electronics to replace a part? May I please have the exact model number so I am able to provide you with accurate, model specific information?
Customer: replied 4 years ago.

I am. the book says 700 series. There is a wiring diagram that says model 700TC ,700TCI would there be any other numbers you need. And could we maybe do this tomorrow if you are working. It sounds like it might be involved and it's getting toward the end of my day and I hve not eaten diner yet. TMI?

Well, the electronic control will likely need to be replaced. The programming seems off. Try unplugging the unit or turning the breaker off for one hour and then we can continue tomorrow after we see what happens after that. Have a nice evening!
Customer: replied 4 years ago.

Thanks Kelly there is an on/off switch can I just turn that off? The LED read out for the compartments temps just shows _ _ instead of a temp and what time do u start tomorrow?

I am on at 7 AM, MST. Unfortunately, it will need a complete power down at the outlet or breaker for the control to reset.
Customer: replied 4 years ago.

I just pressed zone and then warmer on the temp setting and the fan turned on. Maybe it will start cooling I'll check in about an hour or 2 and if it does not I will unplug it and get back with u tomorrow. How late are u in until tomorrow?

I am usually on until about 6 PM, MST.
Customer: replied 4 years ago.

have a good night tks talk to u tomorrow


Thank you, XXXXX XXXXX well!
Customer: replied 4 years ago.

Hi Kelly, I hope you are doing well I had some things come up this morning and then email problems until just now. When a service tech came out a couple of month ago he told my daughter in law that the when the appliance goes into defrost mode there might be a problem with the circuit board or switch that puts it back into regular mode. I turned off the circuit breaker for a couple of hrs last night and then turned it back on and it still was not working this morning although the fan kept going until I switched it off underneath. I am going to be in and out so I wld appreciate if you can work with me and if we don't get it done today maybe tomorrow? Way To Go Chicago Black Hawks

Customer: replied 4 years ago.

Still waiting to hear from you Kelly

If the fan is running, the compressor should be running, too. Can you hear the compressor trying to start, clicking or buzzing at all?
Customer: replied 4 years ago.

The fan runs but the compressor is not trying to turn on. No clicking or buzzing at all

Okay, so the relay on the board is not closing to apply power to the compressor and the electronic control will need to be replaced. That board is available at the link below but they will need your exact model number from the tag on the refrigerator itself.


Thank you for allowing me to assist you! I am happy to answer any follow up questions you may have at no additional charge.


Thank you for a positive feedback rating!

Customer: replied 4 years ago.

Thanks Kelly. Do you know the name of the part?

Yes, it is the control assembly, or some call it the relay board, depending on who you are talking to. It is the part that controls the output voltage to the compressor, fans, etc.
Customer: replied 4 years ago.

Where in the refrigerator would I find it

What is your exact model number, I will see if I can find you a picture. They are usually in the machine compartment above the unit, by the compressor.
Customer: replied 4 years ago.

700TCI serial #M1623129. It is a built in. I don't see any wheels is there any easy way to pull is out. I assume I would need to pull it out to get to the back

Okay, on that model, the control board is behind the area where you set the controls, inside the refrigerator.

SUB-ZERO 700TCI-RH photo Photo0296.jpg
Customer: replied 4 years ago.

Thanks so it should be easy to get to. Are there any other special instructions or things I should be aware of so I don't make a mess of myself?

Not really, only to unplug the refrigerator and be sure to discharge yourself of any static electricity by touching any metal on the unit before opening the new control box.
Customer: replied 4 years ago.

The picture u sent looks a little different than mine at the top on the left I hve the LED read out for the temps and then behind it is the light. So what do I need to do to open it up to get to the relay

Hmmm, that is a bit odd. That is a picture of the model you sent. There should be screws holding the control box in the front and it will tip down when they are removed. Some have small plastic pins that are hidden and pry out, but I am not sure on yours if the pictures look different.
Customer: replied 4 years ago.

Hi Kelly, thanks for all your help. Just one more question I do not see any screws holding the control box so would I pull it forward or down I don't want to break it

I am not 100% sure, but some will pull forward and some have plastic snaps that undo with a little effort. Is there a light cover up there that will come off to expose screws?
Customer: replied 4 years ago.

behind the LED there is a big glass plate with the lights inside that, but no screws. I hope u had a nice weekend

I am not sure at this point what to tell you. I am unable to locate any model specific service information, so I am going to open your question for others to see and perhaps one may have the exact service manual for it.

Make sure the power is off going to the unit.


The side frames of the upper light diffuser have four inverted “T” shaped slots (two each side) which fit over pegs protruding from the side walls of the upper compartment. Retaining clips at the rear slots secure the diffuser to the rear pegs. To remove the light diffuser, slide a finger over the top of each retainer clip flange and rotate the retainer clip down and back. With the clips open, lift the diffuser up and slide it towards the rear of the unit until the center of the “T” slots line up with the pegs. Then lower the diffuser down and pull forward from the unit.

Extract the screws securing the control board enclosure to the ceiling of the compartment. Lower the back of the enclosure while pulling it toward the rear of the unit. Disconnect all electrical leads attached to the control board. Expand the two tabs at the middle of the control board outward while pulling the back of the board down slightly. Then, expand the two forward tabs outward that hold the LCD in position, and pull the control board down and toward the rear of the unit.

If you have questions please use the reply to expert link. If not please leave a rating.


Barry G., Home Appliance Technician
Category: Appliance
Satisfied Customers: 6823
Experience: 27 years in home appliance repair. EPA refrigerant transition and recovery certification type I & II.
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