2001 Dodge Ram Replaced evaporator, now only defrost.

I had to replace my evaporator (and heater core) this weekend. Air nice and cold, but only defrost. It worked fine before I pulled the heater box.

I have vacuum going into the firewall (right past the check valve).

Without starting I disconnected the vacuum line after the check valve, heard vac for a second and stopped, bypased check valve, no difference.

The I disconnected the vacuum block connector under the dash, started the truck, had strong vac for 2 seconds and died down to nothing.

Pinched line maybe?

Assuming I pinched the hose somewhere, where could I run a new hose so I don't have to pull out the hole box, again? What size hose?

Thanks for your input.