Now mechanic says it's the body module regulator that's making my escalade have low fuel pressure and it won't start.

Well the mechanic did check the fuel line and it
was fine I had him check the regulator and he
checked all the coils fuel injectors fuel filter all that
he said was good he pulled the gas tank today and
change the fuel pump didn't tell me if it was bad.
he said that's only thing left it could be. well I get a
call and he tells me it still is not starting that now
he says it is the body module regulator (I think
that's what he called it) its under the seat. He said
it communicates with the computer or brain of the
truck or something like that he said. he's changed
everything else and it ended up still not getting no
fuel pressure he says. So does anybody have any
advice or know anything about this body module
regulator or should I just switch mechanics huh?
Lol