Bissell rug cleaner 25a3 will not spray. How do i fix?

If the pump is engaging, then there may be a kink in the waterline. Follow the path from the supply tank to the sprayer. If that checks out, then there may be a clog. A small piece of debris in the supply tank can end up clogging the nozzle of the sprayer. If your nozzle is removable, that is easy to check and clear up. If it is not, then you have to get a bit more creative. Using a small enough diameter rubber hose and a bicycle pump, you can blow out most debris. Cut the rubber hose to about 1 foot in length. Attache one end to the nozzle ( this may take some doing) and the other to the bike pump. With the supply tank empty start to pump. You should have a modest amount of resistance. If it says "no", then you definitely have a clog. There is really nothing to break so applying more effort to the pump should break loose whatever particles are in the line. Good luck!