I thought only the 98’s had a relay behind the glove box?
Either way, the resistor and second relay is made to make the pump sort of a two speed setup. If the relay is not energized, it sends power through the resistor to reduce voltage. If the relay is tripped, it takes the resistor out of the circuit and sends full voltage to the pump.
If you really believe your issue is voltage at the pump, run a wire from the battery hot and send full volts to the pump (with a big enough wire, and only temporarily). Then drive the car with the normal power circuit out of the equation.
It is a return system so having the pump full speed will be no problem.