Can't tell you for sure about flowing through the inline, but I would assume so. Don't some aux systems only operate under certain conditions or when commanded? (getting into some stuff I don't know much about )

I would not think that the ground on the aux pump would have an effect of the stock one.

 

Shoe
I went ahead and pulled all power off to boost pump, Turned key no noise from fact pump, Then applied power to prime connector no noise from stock pump.
Have you heard of the stock pump going bad with only 5,900 miles?

Maybe from sitting?
Any other ways to check or am I out of luck?
Frank

 

Anything electrical can die when it decides to.

Unless there is something wrong with the harness from the connector under the car to the pump, then I guess the pump is gonna have to come out.

 

Shoe
Thanks for your input!
Frank