We received the defrost timer, removed the old one and inserted the new one.....nothing happened, did not come on, is there some trick to installing this?
Do not know what you mean by "did not come on"
Defrost did not come on OR the compressor did not come on?

The freezer goes from 40 degrees to 70 degrees, we have replaced the defrost heater/thermostat, cleaned all coils etc. The compressor comes on as do the fans. Now what? HELP!!!!
As I said on your previous post.

If there is no ice on the evaporator coils in the freezer section, then you do not have a defrost problem.
Even if the coils were iced up and you manually defrosted the fridge, it would not cause a no cool problem.
If the evaporator coils are clear and the compressor is running you either have a low freon condition or the compressor/sealed system is shot.

I am sorry but I do not know how to put it any plainer so maybe an example will help.
Lets say your evaporator coils are totally iced up giving a poor freezer temperature. You go ahead and manually defrost the coils with a hair dryer.
When you turn the unit on again it should cool down and work correctly until the coils ice up again to the point where the fan cannot pull air through them. The coils will take at least a couple days to ice up bad enough to cause a problem.

You also said in an earlier post that only the bottom section of the evaporator coils were iced up. An uneven frost pattern on the coils is a classic symptom of low freon.