Hello my name is Zack and this is my first post, I have looked and looked and cannot find anything like my situation and need some help. So honestly I am stumped and don't want to throw anymore money into my truck until I get some help. I have had a 99 ranger 2.5l 2wd for maybe two months now and just recently the heat just gave out. Before the air wouldn't blow hot at idle but after getting on the highway it would blow hot air. Finally it just blew cold all the time. So I changed the thermostat, and both coolant sensors (gauge would go up and down constantly). Didn't work so flushed the system completely and during that it seemed like my heater core was not functioning properly so went and changed the heater core along with the heater valve that is inside the engine bay(broke an end off trying to unhook a hose). Still no heat and my gauge stays low. My scanner is reading about 185 degrees sitting at idle then drops to around 140-150 while driving. Any help?

 

Welcome to the forum

The heater valve in the engine bay is an ON/OFF valve, it doesn't control "heat" in the cab except to cut it off completely
It is used when setting in cab is OFF or at MAX AC only, any other setting the valve will be open and coolant will flow thru heater core, the vacuum for this valve is from a grey color line that comes from inside the cab thru the firewall so NOT an engine vacuum line, that would close this valve all the time and no heat in cab

After warm up are both heater hoses hot at the firewall?
If so there is flow thru the heater core, if one hose is cooler then there is no flow

Inside the cab the COLD/HOT **** controls the Blend Door, its an electric motor/actuator that diverts air from the fan either thru the heater core(HOT) or around the heater core(COLD) and anywhere in between
Blend door actuator was a common failing on Fords

Google: Ford Ranger Blend Door

Loads of videos/info on testing and replacing this unit

 

Thanks for the reply. One hose is slightly warmer than the other for the heater core. Also another thing I noticed was there wasnt a vacuum line hooked up to the valve when i replaced it so there still isnt one connected to it and I am not sure where it would be to look for it.

 

But are BOTH hoses warm/hot?
If so, next stop is the blend door

The grey vacuum line will come out of firewall between inner fender and Fan/blower housing, lower down, there will be a Black line with it, so two vacuum lines, they "look like" wires
But if valve has no vacuum it won't effect heat in cab

 

one is as hot as the upper radiator hose the other is just warm and not hot

 

Reads like the heater core has limited flow

Feel the 2 hoses on the other side of the valve, engine side, see if both are hot, if so the valve is diverting coolant when it shouldn't be(no vacuum)
So a bad valve
You can remove the valve and put in 2 hose couplers so flow to and from heater core is guarantied, unless you think the new heater core is the issue

 

So i was able to check it out today, drove it for about 30 mins and no heat at all like stated. Let it idle for about an hour straight and the temp gauge increased and some heat started to come out but it would do the same thing before as well just on idle. checked all 4 hoses connecting to the valve, the lower two were both very hot, one going into the firewall was the same temp, but the other going into the fire wall was slightly less hot, not warm but still hot. So now what?

 

Operate the Blend Door, turn **** from COLD to HOT and back to see if air temp changes, I know it won't get hot but it should get stone cold, so temp should change if blend door is working

But it does read like Valve is not working like it should, one of the "lower hoses" should be same lower temp as the firewall hose
I would get 2 couplers of the right size and pull out the Valve to see if you get HOT on both heater hoses at the firewall

The hot coolant comes out the top heater hose on the front of the engine(near thermostat)
It flows TO the valve, then THRU the valve to firewall
Hot coolant then flows thru the heater core and comes out the other firewall hose
It flows THRU the valve and other hose to the water pump where its recirculated

So the flow out of heater core/firewall to valve then to water pump should be the same temp

If valve is leaking and letting HOT coolant pass to "the other hose" and back to water pump then you will have very low or no flow thru heater core

Engine/thermostat area>>>>>>>>>>>>>>>>>>>>valve>>>>>>>>>>>>>>>>>fire wall/heater core
Water pump<<<<<<<<<<<<<<<<<<<<<<<<<<<<valve<<<<<<<<<<<<< <<<<firewall/heater core