Diagnosis
The pump or the spray nozzle is clogged. Hard water minerals or dried cleaning solution can build up and block the flow.
How to Fix It
First, run a vinegar solution through the system. 1) Fill the clean water tank halfway with white vinegar and halfway with hot water. 2) Without a pad attached, hold the mop over a sink or bucket. 3) Press the spray trigger repeatedly for a few minutes to flush the system. 4) Rinse thoroughly by repeating with clean water only.
If That Didn't Work
Check the spray nozzle itself, located under the mop head. Use a toothpick or pin to gently clear any visible debris from the tiny hole.
Heads Up
Always use the Bissell cleaning solution or a vinegar/water mix they recommend. Thick, homemade soaps or essential oils are a surefire way to gum up the pump.