Air leakage and odours

[Alwayslearning22]

Hi all, 

 

I’ve noticed damp odours coming from sockets on an exterior wall in my new home. It’s only one wall and it’s about 4 metres. The rest of the house is good. 
 

I’m afraid the smell is coming from

behind the air tightness memebrane as It must havre

some punctures in that area.  So I’m thinking is there mould on the studs or insulation?
 

 

 If it were your house what would you do? Where would you start? 
 

thanks