Intermittent rear blinker, and intermittent air from vents

Hello,

My 2006 Aveo is having some mysterious electrical issues.

The rear blinkers will sporadically stop working, causing the front blinkers to blink quickly. Sometimes it's the back left one, and sometimes the back right one. Smacking the offending rear blinker a couple times seems to temporarily solve the problem (lol), but obviously I don't want to keep having to get out to hit my car in public.
To me it seems like a deeper issue than just a bad bulb, but I have yet to check to see if they're loose.

As if that wasn't weird enough, recently the air has occasionally stopped blowing out of the vents. It seems like it gets worse when it is cold out, which is when I need it to defrost my windscreen. When air blows, the AC is frosty cold and the heater gets nice and warm, so that isn't the issue.
I saw a YouTube video about changing the relays in both fuse boxes that relate to the blower motor or something like that, so being the cheap ass that I am, I identified those relays and switched them with the relays that control the fog lights. This seemed to fix the issue, but a couple days later it stopped working again.

To me, if an electrical circuit is broken somehow, I would expect it to stop working and not start working until the circuit is completed again. But in this case, it is all intermittent and it's confusing the hell outta me.

Any help would be muchly appreciated!
Regards,
Caleb

Loose, or corroded bulbs can give you that brake light issue. On the AC, if you are low on refrigerant, it can cut on and off, depending on ambie temperature.

Thanks, I'll take a look at the bulbs today.
I don't think refrigerant is going to make a difference if there is no air of any temperature coming out of the vents sometimes, yet the AC is cold when it actually turns on.