Good afternoon, firstly can you help me with the make and model of the vacuum?
Secondly, we need tof ind out if the suction is due to the vacuum itself or the pipe\head, to do this remove the hose from the vacuum, and turn it on, place you had where the hose would normally go and see if the suction is significantly different than when you place your hand at the end of the hose, if it is, it suggests you have a blockage in the hose, if it isnt, it suggests you need to clean the vacuum filters and check there are not blockages in the inlet.
Let me know how you get on.
What part isnt working, are you getting suction from the vacuum once you remove the hose?
Have you replaced the filters in the vacuum?
Without knowing which model its difficult to tell you where the filters are located but if its a bag-less vacuum its normally located in the top of the waste cylinder.
If the filter has been replaced\cleaned and you continue to have no suction its most likely a faulty duct, which would make it uneconomical to repair.