Blows Hot

[Conniption]

1995 Explorer 4.0 - HVAC blows hot all the time even with the system switched off. Understand this is likely the heater core door, but system also blows hot in MAX A/C mode. Replaced the heater control valve and it does not actuate in any control setting. What to check next?

 

[1998Exp]

Quite possibly a blend door problem. There are dozens of posts on the subject on this forum. Incidentally, the easiest way to search is not to use the search function here, but to enter something like: "Blend Door site: explorerforum.com" into google. Good Luck!

1995 Explorer 4.0 - HVAC blows hot all the time even with the system switched off. Understand this is likely the heater core door, but system also blows hot in MAX A/C mode. Replaced the heater control valve and it does not actuate in any control setting. What to check next?

 

[1992fordgreen]

The blend door at of the "Ex" additude. Get that actuator replaced. Worst case scenario, it's the heater core plenum housing where the blend actuator arm inserts into the plenum. Cheap crap plastic.

 

[Conniption]

So does anyone know why the diverter valve does not actuate when MAX A/C is selected?

 

[RomeovilleIL]

That valve is vacuum controlled. Have the check the vacuum lines and the vacuum ball that sits in the front passenger wheel well. Good chance there is a break somewhere.

 

[rollinstone]

Pay attention to the remarks about the blend door which is prolly 95% the problem. It's an easy and inexpensive fix. Check this out first. It's unlikely that the problem is a bad actuator...could be, but unlikely...or any of the other issues you've mentioned.

If the blend door hinge inside the plenum that fits into the actuator sprocket has snapped (cheap plastic) then all other functions are not going to work including the AC settings. Your blower is going to blow air at whatever temp was set when the door hinge snapped/sheared...even the AC.

 

[Conniption]

Finally got around to repairing the blend door with an after market fix. Door works fine. Now, I had removed the control valve, plugged the lines to and from the core, and direct connected the two hoses from the cooling system at the forward side of the valve. After re-connecting all, I cannot seem to find the vacuum line to the control valve. I had plugged and taped it over when I disconnected everything last Spring, but now it has disappeared. Does anyone have a schematic of where that vacuum line connects to the rest of the system and where can I buy a replacement with the proper end fittings? Thanks. Happy New Year.