Refrigerator not turning on often

[serge1966]

I have an older fridge, presumably GE TFX22CRBAWW, which started causing some issues earlier this year. What happened was it occasionally failed to turn the compressor on when it was supposed to. Initially I just turned the defrost timer wheel and it turned the cooling on, but it did not work all the times.
Later, I knocked the panel where the timer is installed and it turned back on again. Sometimes I had to do it multiple times before it turned on. I ended up replacing the Defrost Timer and forgot about this issue for half a year.

Recently I started experiencing the same issue again, frequently. So I am wondering if it may be a different issue than the timer. Technically, if the timer wheel is stuck, it is supposed to be in defrost cycle, but this is not the case.
It should not be the start relay since the source of the issue is close to the timer, at the top area, not down by the compressor.
I found "Refrigerator temperature control" element on the fridge diagram
Model #TFX22CRBAWW GE refrigerator - b series
But wondering if this type of issue sounds as it could be attributed to the temperature control?
Any help/advise would be much appreciated.

[Vance R]

1 hour ago, serge1966 said:

But wondering if this type of issue sounds as it could be attributed to the temperature control?

Could be either one, next try wiggle one then the other. Odds are it is the thermostat since the timer is newer. 

[serge1966]

Thank you so much! This makes sense. I removed the plastic compartment cover on the day when posted this question and so far everything works fine. So there may be a bad contact and wiggling should help. At this point I don't know if I want to wait until the issue shows up again or try to address it now. Given the situation, it will be difficult to confirm that it has been addressed. Also, I think I can clean the contacts of both thermostat and the temp control at that time.