Boost switch
 

Is this the boost switch and how do i test it.
Thank You

That is the throttle position sensor in your picture. On a 930 it is a simple position sensor either off, on or full throttle.
The overboost switch and the boost sender is located on the intercooler. The red booted one is the boost sender to the gauge, the smaller one that looks like a bolt with an electrical tab is the overboost switch.

Thank you found it.