Bissell Proheat Pro-Tech #7901 will not spray any liquid to the carpet and red cross indicator is not...

the water head are pluged use a tooth brush and some hot hot water and brush it on the tips until they are unpluged

Thanks to many others who have posted on similar problems -- water and/or solution sprays through the handheld tools, but not through the main machine.

As others have suggested, I removed the water reservoir, which exposes the 2 main water sprays mounted above the rollers. Using, pliers, I carefully slid the clips back. Gently but firmly removed the two red nozzles.

Elsewhere I have read suggestions to just do one nozzle at a time. However, I found out that if you remove both red nozzles, you can then blow through one side and it will come out the other. In my case, that dislodged a nice collection of crystal-like chunks (guessing it may be crystallized residue from the cleaning solution).

There was also a bit of blockage in one of the red nozzles, which I cleaned out. Make sure you can blow through both of them with little resistance.

Reassemble: Push red nozzles back into hoses. Using pliers, reposition sprung clip back over the red nozzle. Snap nozzles back into place. Refill tanks and power it up.

In my case, that resolved the problem of no sprays from the main machine. Sprays like new now. Hope yours does too!!