Engine noise from refrigerated trailer

[FastFred]

This is actually a really simple one to add I guess.

The A/C units on refrigerated trailers make a constant noise, even when the truck engine is turned off. They run of their own fuel. Please add this noise.

Obviously in ETS3, I want to be able to get out of the truck and set the temperature manually and have to get out at every stop to check if the temperature is still good or else the load gets damage. But lets not go to far now.

[Dr_Jaymz]

also the aire conditioner/ in cabin heating has their own sound...