Ranger Heater Valve Function

[MrGiggles]

I've been having a little trouble with getting this truck to warm up like it should. The gauge always read C or just above it. Replaced the thermostat and both temperature sensors, which didn't help.

Yesterday I think I found out what the problem is. This truck has a broken blend door, and the PO got around it by putting a manual shutoff in the heater hose. Yesterday, that valve backed off, it started blowing heat, and the temp gauge was riding in the middle just like it should. Coolant needs to flow through the heater hoses for the thermostat housing to remain hot.

I broke the factory plastic heater valve a couple months ago and just joined the hoses where it used to be. It was still not warming up with it in place, but the vacuum line was not hooked up.

So, how does the stock heater valve work? If I replace it and ditch the manual valve, will it still block coolant from the heater core, but still allow coolant to bypass so the temperature gauge reads like it should? Or do I need to make my own with a pair of valves and a bypass hose?

I really don't care about the blend door, I've always just turned it on and off anyway. Full heat or full cold is fine with me.