Gilly,

I recorded the following information using the procedure outlined in the linked site:

Key for Measured Attribute______11/19 OK__11/20 Malfunctioning__11/20 OK
1.In-car air temperature sensor:____73 _______76_________________80
2.Outside air temperature:_________87________48_________________48
3.Left heater core temperature:____98_______130_________________69
4.Right heater core temperature:__100_________87________________71
5.Evaporator temperature sensor:___39_________39________________40
6.ECT sensor (DFI, IFI):__________177________170_______________168
7.Refrigerant Pressure in bar:_______15_________04________________04
8.Refrigerant Temp Sensor (F):_____125 ________57_______________51
9.Not Used (but has numbers?):_____40_________51_______________51
10.Blower control voltage:___________6.0________6.0_______________6.0
11.Emissions Sensor (voltage):_______2.6________2.2 _______________2.2
12.Sun sensor (voltage):____________4.3________4.3________________4.3
20.Aux. fan control current (amps):__10.3________3.2________________3.2
21.Engine speed (x100=rpm):________4.2_______69_________________60
22.Vehicle speed (km/h):____________0.0_______67_________________37
23.Terminal 58d (%Battery Volts):__211________211________________211
24.Battery Voltage:_______________12.8_______12.9________________12.9
40.Software Status:_____________164________164________________164
41.Hardware Status:______________32_________32_________________32
42.Unlisted/Unknown:_____________72_________72_________________72
43.Unlisted/Unknown:____________152________152________________152


It should be noted the car was idling in the first set of recorded data, after being fully warmed up and driving for about 25 miles on the highway. The air conditioner compressor was shut off, with the system set in "Economy" mode and the system was operating more or less as it should, with about equal temperature (cool) air coming from all four dash vents. The outside air temperature reading is way off because, in all likelihood, the engine operating had warmed the air under the car, giving a false high reading for the sensor under the front bumper.

The second set of readings took place on the highway with the air conditioning compressor on (by pushing the "Economy" button to turn it and the little red light off). After the system was operating normally for a while (more than 5 minutes), the system switched itself into its autonomous mode. In this mode the system operates with very hot air spewing out the driver's side dash board vent and footwell while the same vents on the passenger side were cool. Even the driver's side center outlet was warm while the adjacent passenger side center outlet was cool. The temperature settings were set in "Automatic" and "72" on both sides for the duration of this event, including while the readings were taken. I question a number of the identifyers in the chart referenced on the previously linked site, which I have copied over in the table above. Items like the rpm and the vehicle speed just don't make sense so I imagine there is a newer key to figuring these things out.

After recording the data for the condition noted in the second column above, I put the unit in "Defrost" mode for about 5 minutes, cooking the inside of the car. Then I switched the "Defrost" mode off by pressing the push button and the system recovered, the compressor came on and the cabin cooled pretty quickly. The third set of data was recorded while in this recovered condition while driving initially on the highway and then the last few miles on a side road.

When I look at the data the most obvious thing is that when the system is in autonomous mode, the heater core on the driver's side is pretty hot and the one on the passenger side is not. So something is telling the valve to open or the pump to pump. Any ideas? The rest of the stuff looks pretty normal to me. Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)