2008 Ford Explorer hissing hvac?

[stuartyager4437]

So this issue started as a hissing coming from the passenger side. Then we would have the shift in the AC from passenger AC to defrost while going up inclines. Now the AC barely works on the passenger side and it doesnt get cold at all on the driver side. I want to fix this myself. Please help.

 

[07EddyB]

Search check valve. Located close to the firewall in the engine compartment. Common issue.

 

[stuartyager4437]

Search check valve. Located close to the firewall in the engine compartment. Common issue.

The valve appears fine. Would this also cause a loss in AC coldness?

 

[PotatoExplorer]

I think it would. I'm thinking that if the check valve is failing, it could cause the blend door to not open allowing cool air into the cabin.

Check this thread: http://www.explorerforum.com/forums...noise-when-accelerating-then-dies-out.303106/

 

[Rcflyer330]

Most likely the check valve. The one way valve may test good if you use your mouth and either blow air through but that would be the first thing I would replace they are a very common failure point, I have a 2010 and have replaced mine twice within the last two years. Do you have dual side climate controls?

The ac coolness may be a problem with the ac system check the compressor clutch see if the compressor is turning on and if you have a manifold gauge check the pressures. My car has rear heat and ac and the compressor was turning on even know the system had a hole in the line going to the rear under the passenger rear door.