Defroster and heat issue

[Rambug]

Im hoping someone here might have some insight, so heres my problem as best as I have been able to note thus far.

Defroster is WEAK this morning, at 32 degrees it took a full 50 minute drive to get half the fog from the window...HALF

Now for the second issue...
My heater...
for some reason, it works great on the passenger side of the car, but the drivers side blows out cool air.

Any info is greatly appreciated.

 

[EWC88]

I'm not positive but thinking maybe heater core? I need to replace my heater core, how I know; smell syrup, to heat truck it takes FOREVER even with defrost. I also am replacing blend door and evaporator so I have no worries anymore under the dash.

 

[Rambug]

I know I probably do need a heater core as I smelled the syrup myself, but like I said, the passenger side heat works great...I'm baffled