2003 GMC 2500HD won't start

[Psdgunner]

Truck won't start and I got a code of;
P0335
Crankshaft position sensor A circuit malfunction.

Any ideas on how to fix this...

 

[wdino73]

I would start with the obvious an check the harness an plug, my moto is KISS
Kept, It, Simply, Stupid,
That's what I always tell myself.