Originally Posted by marchyman
It's reported job is to reduce power (voltage?) to the fuel pump as full power is not needed once the fuel system is pressurized. The reported reason for doing this is to lessen wear and tear on the fuel filter that is an integral part of the fuel pump. Other models have an external, replaceable fuel filter and do not use the controller. When you bypass the controller with the cable you are running full power all the time.
I'm just parroting things I've read... I really don't have a clue as to how much of that is factual.
OK, I really don't have a clue.
I think it's just OVER-doing what it was intended to do. If it shuts down the fuel pump altogether, it'll NEVER wear out - thus it'll have an infinite life expectancy!!!