Having the window open just amplifies the awning rattle, I doubt it’s your window, the window runs in a rubber seal, which should prevent it rattling
if you think it’s your window when open : whilst the window is open, try pushing the window down wards and pull it toward you a little, so it is tight against the rubber seal, I bet the rattle is still there ?
if so it’s you’re awning.
Solved the awning rattle:
I have the anti rattle plastic clips which have severely improved the awning rattle.
I was still getting a rattle particularly when driving on rough roads (everywhere) With the drivers window open, which I find Really annoying.
long story short, the awning leg (top cast joint ) is able to move enough to allow the support leg to hit the upper awning casing (even when clipped in correctly to the plastic leg holder in the middle of the awning).
This can be checked by partially opening the awning approx 100mm , push the top part of each leg joint casting upwards, you’ll see it move, the leg joint is riveted and has a swivel joint, allowing it to move upwards with relative ease & allowing the leg to hit the main casing inside, (causing a intermittent rattle)
decided to try fitting a couple of bits closed cell plastic foam, (the Type you get in packaging with phone cases etc about 4mm thick ) .
I used two pieces cut to the width of the inside of the awning casing directly above the leg storage position & 70mm long , fitted them lengthways, directly above the upper leg cast hinge position, about 40mm in from either side of the attachment point for the leg hinge, attached with automotive double side sponge tape.
this created enough support to solve the rattle even over very rough roads.
very simple highly effective fix to a highly annoying rattle, hope this is useful