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Climate Control-one sided heat

1592 Views 8 Replies 4 Participants Last post by  mannfrm
Good Morning-

Texas weather has been nice till this week when we got our first freezing temps.
My 1994 w140 climate control was not up to heating the cabin sufficiently. I ran the sensor value test.


est Step Sensor Value Display
1 73 In-car temperature sensor w/ aspirator blower (B10/4)
2 72 Outside temperature sensor (B10/5)
3 86 Left heater core temperature sensor (B10/2)*
4 87 Right heater core temperature sensor (B10/3)*
5 35 Evaporator temperature sensor (B10/6)
6 87 Coolant temperature sensor (B10/8)*
7 11 Refrigerant pressure in bar (06 = 6 bar)
8 14 Blower control voltage from B(min) - 60(max)
9 20 Software status

Also, performed flap test and found 3 to 4 of primarily driver side flaps did not seem to operate by ear. So, I turned heater on and checked both sides of compartment for air flow. I found that I was not receiving heat from most driver side vents and if any air flow was found, it was non-heated air. Passenger side vents were operating and I could feel heat. Turned on the red button on center vent and received heated air on passenger side but none on driver side.

My questions are:
-the above sensor values look correct except #5. Do I have a evaporator sensor out?
-Is the non-performing driver side attributable to a non-functioning duo-valve or possibly a Y11 vacuum block malfunction?

Those are my questions from reading through the archives. Any help will be appreciated.

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samosali - Thanks for the info on the evap sensor. OK, will perform test this weekend and clear errors from CC.

nhzruthless818 - Turned defrost on this morning. Good airflow from driver side windshield vent but not so much from passenger side. Air was cool, not warm on driver side.

Thanks to both of you for replies. Will report back what I find this weekend.

Ran trouble codes today. only code I received was EO 43 (A/C system temp sensor (B10?8), open or short circuit). I cleared the code. Would that affect air flow from vents, also?

Update on climate issue.
I replaced duo-valve I received from nzhruthless. That fixed my heat issue since one side was blocked. Then I replaced 3 actuators behind the dash to repair my vent problems.
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