Replaced monovalve-now my AC has hot air mixed in

[jpjp22]

I have a 1986 300SDL. I replaced a torn monovalve last night and now I have hot air mixing with the cold air. The only place it feels a little bit cool is in the left/right lower vents (not the one where part of the vent in a "fixed-vent" to blow on the windows).

I know there are hundreds of threads about A/C and heat but I was hoping someone might have quik fix or something to check.

This was bad timing as it's 95 degrees here in Dallas today. I had no heat last winter but it really only bothered me on one road trip. I thought I would go ahead and replace it but if I don't figure something else out pretty quick I will put the torn one back in until winter time.