Hi everybody.
Pls. give me a tip or two about my A/C problems.
When I switch on the sys. ,compressor clutch engage,blower works just fine but the driver side vents deliver only hot air and the passenger side vents only outside temp. air.Also defrosting vent gives me only hot air and the vents under the dash don"t deliver anything.
The sys works like this and does"nt matter wich buttons I hit (EC, REST,AUTO,RED or BLUE button between centre vents).I change the filter on top of the blower and I notice that the recirculation flap is not working when I hit that button.That flap is allways open.
What"s your opinion?
Duo-valves?Vacuum?Both?...Something else?
Tnx in advance.

Testing the duo-valve is a good starting point..The a/c pushbutton MUST send ground to the valve for it to shut-off.

If you have both ground signals at the valve then it MUST shut off all of the water flow.

The valve has a 3 pin electrical connector...center pin the the power. 2 outer pins are the ground signals..test with volt meter w/ key on & connector still on the valve.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I"ve checked the power supply between the midlle and both ground wires.It"s ok(12 V) Continuity for both valves ok(about 14.8 Ohms) ,more then this, they are clicking (both of them) when i connect the power supply.I"ve run the DTC"s test too(shows me just E000,and nothing else).I"m in "dark" here MB.DOC !!! Pls give me one more tip about this A/C problem
Tnx for your help.