Air blower issue and un-tightened hose connection

Back with another issue, one that seems kind of familiar (ran into very similar issue last year, but so far same solution doesn't seem to work.)

Car is blowing cold air, the AC portion is working, but it's blowing very little (ie the blower seems to be having issues.) If I lower the blower setting down to 1, then back up to 7, the blower will kick in, sometimes half-heartedly for ,a minute or two, sometimes only for a second or so. Then it goes back to doing almost nothing.

Last year I replaced the filters, and things seemed to go perfectly back to normal. Today I replaced the filters again (not for the first time since last year, I don't think), but no improvement. Tomorrow I'll take off the cable from the 12 volt battery and leave it off for a half hour or so, to try and force a reboot of the system to see if that might fix things (hey, it's possible), but if that doesn't work, suggestions of possible issues?

If I have to replace the blower motor, how difficult, involved, and expensive is that?

ONE OTHER THING: While changing the engine air filter, I noticed something. They removed the filter and filter case while replacing the water pump back in March ... when they put it back together, they pushed the hose connection part back to the top of the filter case, but they didn't tighten the bolt on the little silver thing that tightens it down, so the connection is very loose? What kind of problems has this likely been causing me?

Any info on these two matters would be much appreciated.

 

Haven't been having those problems (that I've noticed), and it DID make it easier to change the filter.