1. Is it snow or ice?

2. The defrost thermostat senses the cooling coil temperature and operates with the electric current to the defrost heater.

3. If there is snow on the coils - yes. If there is ice chunk(s) then the problem is more serious, probably the sealed system.

Gene.

There is no a defrost timer in Samsung refrigerator. This refrigerator operates by the electronic control boards. You can check the defrost thermostat and the defrost heater for continuity. If there is nothing wrong then the control board has to be replaced.

If the defrost thermostat is bad you can replace it yourself, but if the defrost heater is bad then the whole evaporator assembly has to be replaced and it has to be done by a certified technician.

Gene.

Hi Gene,
How do I check for continuity? Or where? Did I mention the whirring noise from the fan or the motor? Would that tell me the bearings are out and I need to replace the motor?
Thanks Gene :o

Allysmom,

Samsung refrigerators are not very simple and not many technicians know how to fix them. It is very easy to damage an interior panel in these refrigerator if you do not know how to handle them right. I would recommend to call a Samsung authorized guy to diagnose and fix it for you. DIY can cost you more money with this fridge.

You can learn how to run a continuity test from the following article on our forum - How to check Continuity with Ohmmeter.

Gene.

Gene,
Here is the full dialogue that we have had thus far; I'm including it because I think we might have gotten caddywompus. I know you talk to a lot of people about a lot of issues, so I thought it best to include the full context.
2/8/09 To Gene from David.
Gene,
I've read your posts regarding defrost system, and am convinced this is my problem; but I'm puzzled still. First, I'm puzzled why my model # doesn't show up on any sears parts website, but model #'s that are very close do show up; so I have used parts diagrams from the very similar model# 25359482991. My original symptom was warm refrigerator, which led me to find ice on evaporator coils. I manually defrosted evap coils, then plugged back in, and it worked fine. The defrost system kicked in regularly, and I could see ice on coils melt. It worked great for a month. Yesterday, same problem reoccurred. So, I defrosted evap coils manually. I found your post on defrost system, so I located defrost timer, turned to advance until I heard click, observed defrosting evap coil, after 35 minutes, timer clicked and freezer started back up. All seems like it is working fine. However, I am confused why the ice buildup a month ago, and again yesterday. I have not done a continuity check on defrost heater because I saw the ice on the evap coil melt when in defrost mode, so it must have continuity. What is your best guess? Thanks, David.

2/9/09 From Gene, To David.
Hi David,
The only part in the defrost system which can have an intermittent problem is the defrost timer. In the situation you described, I would replace it first. The defrost thermostat could do it too, but it is much rare.- The part number for the defrost timer is AP2111929 Gene.

2/9/09 To Gene from David.
Thank Gene; I ordered a defrost timer yesterday and it should be here tomorrow. If that's not it, I'll call again; otherwise, thanks a lot. David

2/9/09 From Gene to David.
You are welcome. Keep us posted. Gene.

2/28/09 To Gene from David.
Gene, After I replaced the defrost timer 5 weeks ago, everything seemed to work fine until today; coils in freezer are frozen up again. As I've read your posts, it seems the only defrost components are timer, thermostat, and heater. You stated the only defrost components that could be intermittent were timer and sometimes thermostat. I've replaced the timer. I've never understood what the defrost thermostat really does. Do you advise to replace it next?

2/28/09 From Gene, To David.
1. Is it snow or ice?
2. The defrost thermostat senses the cooling coil temperature and operates with the electric current to the defrost heater.
3. If there is snow on the coils - yes. If there is ice chunk(s) then the problem is more serious, probably the sealed system.
Gene.

3/3/09 Gene, Back to this message: Given this continuous dialogue, I am now somewhat confused. The answer to your question #1 above is "Ice". But that was my initial problem in the first place (see 2/8/09 post above). Your initial advice was to look at the timer, which I replaced (see 2/9/09 post above). From your secondary advice (see 2/9/09 post above), I have ordered a defrost thermostat; it has arrived, and I will replace it tomorrow.

My current confusion is based on your #2 and #3 above. Regarding #2: can you please explain the relationship between the defrost timer and the defrost thermostat? My current understanding of my defrost timer is that it is a clock that runs on 8.5 hour intervals to switch the defrost cycle on; which would turn on the defrost heater; which then runs for 35 minutes timed by the defrost timer. So, how does the defrost thermostat have a role in the defrost cycle if the defrost timer is the switching governor?

Regarding your #3 above: since my first post, I've had ice on the condenser coils rather than snow. Also, I've only been focused on figuring out which of the 3 defrost components is the issue, and have not been led to consider any other parts or systems. But your #3 above leads me to believe that you think my problem is other than my defrost system.

So, do you have a logical procedure for me to go forward with that can help me identify the issue?
Thanks so much for all your help, Sincerely, David