Center vent semi working?

[MC34]

Good evening!

I bought my car just before the summer. Weather was very hot so I only used cooling for the past few months.

AC was on, temperature was set to 22 degrees celsius (~72 fahrenheit), ventilation was set to "Auto", dial on center vent was set to "3 blue dots"
It was working very good. I could feel very cold air blowing from the center vent.

Yesterday we had big weather change. Temperatures went from 35 to 15 degrees celsius (95 to 60 fahrenheit) so I needed some heating.

AC was off, temperature was set to 22 degrees celsius (~72 fahrenheit), ventilation was set to "Auto", dial on center vent was set to "3 red dots"
It was heating very, very slowly. I was confused so I put my hand over the center vent and only right side was blowing warm air, left side didn't blow anything.

My questions are:
On "3 blue dots" both sides are blowing good, but on "3 red dots" only right side is blowing. Why is this happening?
Is it supposed to heat this slow? I drove some cars from the 90s with manual vents and they were blowing way hotter.

My car is running very good. Never had any problems with it.

I apologize if this was already answered before.

Thank you in advance,

~MC34

[TexasTouring]

Good question, I have had the same issue on my car since replacing the blower motor this summer. Although the issue persists for both heating and cooling. Similar to you, the right side of the center vent works as normal, but the left side of the center vent is much weaker, even with the blower motor cranked up.

I think I might not have put something back together correctly. Look forward to seeing if others have this problem or know the issue.