Gas fume smell in cab

I fill up my truck and can't deal with the smell of gas when I run the heat....
I fill to half a tank and no problem??
Purge solenoid maybe?? - I appreciate any help, there are so many parts to the vapor system and would hate to have to replace it all and I have no codes.
I have a 2004 silverado 2500HD extended cab with the 6.0
Thank you

Any idea? What could be the most common cause. Purge solenoid, purge filter, vapor cannister or am I totally off.
I thought maybe the purge filter possibly from an over fill at the pump.
Thank you for any help.