Shaker starts, rotates, but fans, heater and compressor dont work

I dont know why but when i turn my shaker it starts normally and it can rotate but the frontal fans never turn on neither the one in the back. When i turn the heat on, the indicator light does bright but I checked the voltage in the back terminals with red plastic and they are not powered. When i try to use the compresor for the coolant mode in the shaker it also does not do anything. I checked the voltage on the EWT72 terminals comparing it with another identical shaker that i have to see strange behaviors and the voltages are the same, except for the red terminals ive mentioned earlier. Any advice you can give me? Even though you dont know my problem can you help me to tell me hoy to open my shaker safely for trouble shoot im afraid to damage some plastic or metal sheet