2 resistors 15 ohms each or 7.5 ohms as shown in parallel. About 5 volts to the pump with key on. Actual pressure switch (not vacuum) changes at about 1/4 psi. I can blow in tube and get it to change states.
With vacuum pump runs slow with power through resistors.
With boost pressure switch closes and bypasses resistors and pump gets 14 volts
Theory is to keep the radiator and supply line cold as possible but have the fluid moving slowly.
Looking at insulation CAI, need a black insulated pizza bag.