ML270 2002 Mirror indicators not working

[bloobloo]

As the title, Ive noticed that my indicators dont work on the mirrors. Also they don't fold in when I press the button.
I've looked at replacement light units on ebay and I'm Shocked at the price of them! Am I really looking at between £60 & £90 (each) for them?
Seems a lot for what they are?

 

[JML270]

Check fuses (relay?) and for broken wire(s) in door wiring harness.

 

[bloobloo]

My main indicators seem to work ok, do the door signals have their own fuse / relay?

 

[Blobcat]

I'd guess at broken wires in the door mirrors