Car has no crank, no start, no dash

Ive seen this many times ..so Id say test it this way...If you connect a jumper cable from any metal part of the engine a bracket a bolt anywhere you can clamp onto the engines metal .. and the other end to the negetive jump start terminal i believe on the drivers side then try to start it... if it starts your ground strap between the body and the engine is bad somtimes you can take it off a nd clean it real good sand paper on the ends and where it connects to the engine and the frame rail but most time I just replace them .. ..comon one these bmw cars they used a braided copper cable type ground cable that bolts to the frame rail and usually looks good there but if you follow it down to where its bolted to the engine/bell housing area thats where they tend to get corroded becuase its down on the bottom where lot of rain water and other road scum buils up on it and corrodes it ive seen it many times over the years on lots of German vehicles ..so yeah id say try this and let us know what you find good luck hope this helps

Thank you so much I’ll definitely try this out and let you know ASAP