have you tried measuring the input voltage when its connected to the fridge, if it remains the same when the fridge is turned on and the module has been tested then it has to be the compressor. They do fail but its quite rare. maybe its gone past its heeling angle and come apart inside.
The compressors are still available and it can be removed with some spanners, all going well it wont leak past the self sealing couplings.

steve