My car is 15months old and since month 3 I've had various issues with my gla 20d. The check engine came on for no apparent reason every two weeks.long story short they changed all the wiring to fix the problem. Now I have a strange babbling sound that comes from the ac when I drive for over 30 min and Mercedes dealer can't fix it and are trying to convince me it's normal. Has anyone else heard this type of noise? It's come from within the ac vents and get very loud and irritating at times,I think it's effected by higher temps outside, I live in cyprus and the temprature can get upto 40c.