AC problem
 

Is it possible that if my freon charge is low that I could have cool from middle vents and heat from the outer ducts? thanks

Not likely

Thanks might you suggest a place to start? The car is a 94 c220 w climate control.

If you do a search for " vent actuator diaphragm" or "vac pods". Weeks worth of reading.

Start with the control of the heater valve. It is a pulsed valve and it will have power AND ground when closed. The power will come when the key is turned. The ground is controlled by the AC control unit. In the "low" setting the valve should see a constant ground.

I usually confirm the situation by taking needle nosed vise grips with fuel hose over each "needle" and squeeze the inlet or return hose shut (the fuel hose protects the water hose from the jaws of the pliers) and then drive. By restricting the flow of hot water you duplicate the activity of a closed water valve. If that solves the problem then see if you have electric control. if you do then a bad valve is the logoical answer.

Thanks Steve I appreciate the help...my heater valve has two outlets on one side of the valve and one outlet on the other. The single comes from another main supply valve according to my Haynes manual. My question is can I just crimp the single inlet as you stated and then drive. I'm just not familiar with the flow directions. The top of the valve has two electric solenoids. I assume these are the ones that are directed the module to control flow? Thanks again I'll post after following your advice.

Yes grab it where one crimp will shut flow to both sides. on your car the return is about impossible to crimp so the single line in would do best.

Hello Steve I crimped the single inlet hose to the control valve. I drove for a mile or so the heat still comes from passenger and driver side vents ..the center vent have ice cold air..I guess my question is how can the heat be on with the hose crimped does this not stop circulation through heater matrix? I haven't checked voltage or ground yet. I'll do that tomorrow when I can borrow a volt meter. Is there one blend door that shuts off the heater air flow and accesses the evaporator air flow? I'm reminded of a vw plenum and the vac pod was not changing over? thanks again for your patience.

If you have the right hose and wait long enough you should not get heat. One must recognize the difference between heated air and not cooled air. There are probably some plenum door reasons you could get much colder air from the center. But, heat has to go away when you stop the water flow.

Thanks Steve I will pinch off the fire wall hose by drivers firewall goes back to engine at rear of block and drive again. I will pinch both and see if this makes the flow stop. Maybe the flow is out the single hose of the valve and the two hoses on the other side of the control valve are the inlets. My Haynes manual shows the two supply hoses from the control valve and the single return hose back to the engine.This is what confused me.Two supply and one return. Anyway I will post on progress.Thanks

Hello again this time I shut off the return and the supply and am still getting heated air from side vents and cold air from the two center ducts? Never seen that before. The hoses are clamped with vice grips with rubber hoses on ends to protect the clamped sections.I drove it and nothing has changed.I checked my haynes for flow directions but it is not clear. Steve ,do you have any suggestions. thanks Jerry

Ac Hot Sides Cold Center
 

Hi there , I have the same problem w/ my 94 c220, have you had any luck w/ yours?? I'd love some heelllppp. It's driving me nuts and I get no where w/ the local techs, Thanks , Seth