Hi All,
Just bought my 1st Benz (1999 E300DT). Before I bought it the AC was not working, previous owner took it to have it looked at and mech said it just needed the system reset and that it was probably due to car sitting / low battery. Well AC works fine, but I decided to have a look at the error codes.
Here is what I got:
Sensor
1 - 80
2 - 78
3 - 44 Left Heater Core Temp
4 - 40 Right Heater Core Temp
5 - 32
6 - 159
7 - 15
8 - 114

Errors
B1128 Heater core temperature (B10/1)
B1229 Heater core temperature (B10/1)

From EclassBenz AC diag

• Your A/C system is working properly. The evaporator temperature is 32 degrees.
• If your problem is air flow, rather than air temperature, it's likely that your blower regulator went bad.
• Code B1228 Explanation: This sensor measures the temperature in the left side heater core. It is reporting an implausible temperature or voltage reading.
• Code B1229 Explanation: This sensor measures the temperature in the right side heater core. It is reporting an implausible temperature or voltage reading.

Near as I can tell everything works; AC, heat, blower, defrost, etc. I have searched a bunch of forums and can find nothing on the heater core temp sensors.
Is this even an issue? In my looking around B10/1 is also called Duo-temp sensor and I believe is located behind the radio (or there abouts!).