Which hose is heater inlet 1998

I'm planning on installing a flush kit on my 1998 Intrigue 3.8l.
The instructions on the back of the kit don't seem to apply.
The tee is supposed go in the heater inlet hose. There are 2 hoses coming out of the waterpump, both go to the firewall, is the heater inlet hose the top or bottom one at the firewall?

Thank you.

The lower hose at the firewall is the inlet and top is outlet back to the water pump.

OOOPs.

I took a guess that it was the top one. seemed to flush fine. Do you think it makes a difference?