When should aux water pump run?

[Surfy_steve14]

Hi all. I'm trying to work out when the auxiliary water pump that is in line with the heater core should be running? Is it all the time the the motor is switched on and then after you shut down for a little? Mine doesn't seem to run when the car is on and I have no heat on the dash.

[Transporter]

Do the scan and see if the ECU reports any fault with it. How many km have you done? Also, the pump is PWM so ordinary voltmeter doesn't have to see any voltage, though it's loud enough to hear.