A while back I stopped my 2000 Ford Ranger (V6 4WD) and all of a sudden there was white smoke pouring out from under the hood, indicating that something was leaking radiator fluid. When I opened the hood, I found that a part connected to 4 cooling hoses and one wire had broken:

Close up In context

I've looked through a number of OEM parts supplier breakout diagrams, but I can't find anything that looks like it. It is located in the left rear portion of the engine compartment. Can anyone help me identify this part so I can buy a new one?

  • I know there was already an answer.. But I've explained what this part does as well for clarification in case anyone is as curious as me.
    – DJSpud
    Commented Feb 27, 2015 at 18:40

2 Answers 2


This is the heater valve. It's Motocraft part# YG350:

Pulled from Rockauto.com

  • 1
    Nicely done, @Paulster2. Commented Nov 17, 2014 at 21:03
  • A little more explanation might be nice... I will explain in another answer after UVing you :P.
    – DJSpud
    Commented Feb 27, 2015 at 21:45
  • @Jhawins ... I'm not sure I understand what you are asking. The OP's question was specifically to identify this part, which I did. But that's okay. You've provided quite a detailed answer as well. Looks good, btw. Commented Feb 27, 2015 at 22:05
  • 1
    @Paulster2 I'm not asking for anything. Your answer is 100% correct and it looks like you were pretty damn fast about it too so good job! It just seemed like maybe explaining not only what the part is but what it's function is as well might be appreciated by someone else down the road. It might not though, who knows.
    – DJSpud
    Commented Feb 27, 2015 at 22:11

This is your Heater Control Valve But I am going to explain what it does.

First of all the "wire" you see is actually a vacuum line, it's a hollow (hopefully) air-tight tube that passes vacuum to the Heater Control Valve. The heater control valve is a vacuum actuated valve that in the open position allows fluid to pass through and in the closed position does not allow coolant to pass through. This valve is normally open, meaning that when there is no vacuum present the valve will allow coolant to pass.

On your HVAC controls your options should be [Max A/C, AC, Vent, Vent/Floor, Floor, Defrost+Floor, Defrost only]. When you have the controls set to "off" or "AC" this valve closes to prevent coolant from entering the heater core. In any other setting (I believe, there might be another though) this valve is opened and allows coolant to circulate through the heater core.

This is to maximize AC efficiency because when your heater core is full of (hopefully) 192F coolant you are going to be fighting that to produce cold air. It also closes off this area of the coolant system which increases your coolant system's efficiency as a whole (not having to circulate through an area that doesn't really provide any cooling aside from the heat you draw away into the cabin).

This isn't something you will find on every vehicle as it isn't truly necessary. Lots of vehicles simply allow coolant into the heater core 100% of the time. This means that it can be bypassed as a quick fix if you really need to and don't have immediate access to parts, just connect the lines. Although you probably won't have connectors for the lines either if you can't get access to such an easy to find part ;P

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