Hello and welcome to FixYa;
Make sure the collection tank is not full,
that it is seated correctly
the handle is locked upright to ensure a good connection
between the tank and the rear cover gasket.
Check for any damage with the collection tank cap.
Check the divert knob is set to the tools setting.
Check the motor duct for suction (To locate, remove the water tank.
The motor duct has a rubber gasket that is oblong) with the power on,
place your hand over the hole for suction.
If there is still no suction, call BISSELL Consumer Services toll free
at 1-800-237-7691. A representative from Bissell will help you from there.
KittyTech If you need further help, reach me via phone at
https://www.6ya.com/expert/carolyn_427ff26936286336