Why would you get heat on only one side of 1994 lesabre doesnt have duel zone?

No heat, Heater Hose Replacement

I had/have the same problem on my 92 Lesabre, I replaced the top heater hose which I believe controls the two most right vents and I have "heat" from those two vents. I don't have heat all the time from the left vents because I couldn't change the bottom heater hose, it's very diffcult to reach and get out and replace, I will try again this coming spring, pray for me !! I hope this helps, I got a lot of advise before I read about a possibe answer on a forum like this one! Merry Christmas and Happy New Year !

P.S.S. I suggest that you replace both heater hoses.

One hose is the inlet, the other is the outlet. Is there in fact air coming out of the vent or is the air coming out cold. Sounds as if there is possibly blockage.