2002 Mitsubishi Galant Heating Problems

Here is my problem. There are 2 hoses that run into my car from the engine. One produces heat, while the other does not. In the past I had to physically pump the cold hose(30min) to get the hose to produce heat. And if I switched from heating to air conditioning, the heat would stop working and I would have to do the process all over again. Now that process has stopped working.

Any suggestions would be greatly appreciated!