Weak heater (climate control). No heat out of the center vents. Low flow, (but eventually hot) air out of the side vents.

Engine temp display on the dash never exceeds ~65C
Error codes from the climate control pushbutton display: 
B1231 ECT Sensor (B11/4)
B1234 Sun Sensor (B32)
(See Steve Brotherton's article for code access procedure: http://www.continentalimports.com/ser_ic40142.html )

Does the ECT (Engine coolant temperature) sensor that is used in the climate control system also send the signal to the temp display on the dash? Which has failed, the thermostat, or the ECT sensor? both?

One more thing: 
Individual flap test revealed that the right diverter flap (2) is not operating. All others passed test.

Thanks for your help,

Still reading? Here's some more info that may be useful:

Actual values after driving the vehicle for 20 minutes operating the heater with the outside temp ~25F:

1.In-car air temperature sensor:____22
2.Outside air temperature:_________-5
3.Left heater core temperature:____43
4.Right heater core temperature:___42
5.Evaporator temperature sensor:___34
6.ECT sensor (DFI, IFI):___________65
7.Refrigerant Pressure in bar:_______02
8.Refrigerant Temp Sensor (F):_____-1
9.Not Used (but has numbers?):_____-5
10.Blower control voltage:_________3.1
11.Emissions Sensor (voltage):_____2.1
12.Sun sensor (voltage):__________4.2
20.Aux. fan control current (amps):_0.0
21.Engine speed (x100=rpm):_______06
22.Vehicle speed (km/h):__________00
23.Terminal 58d (%Battery Volts):__00
24.Battery Voltage:______________13.1
40.Software Status:______________71
41.Hardware Status:______________34

Other notes:
Fans feeding the interior temp sensors located in the overhead console appear to be working (will suck and hold a scrap of paper against the grate)

During the summer when operating the AC: Upon start up one vent might blow hot air while the others are chilly. Running the defrost for 30 seconds and returning to Auto usually gets it running properly again.
1998 E300D 1-tank Elsbett Veggie system
1986 190D 2-tank Veggie system -Sold