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Discussion Starter · #1 ·
I replaced the right temperature sensor same problem. I unplugged the climate control switch panel and all the values go to 32 tested the sensor plug for grounding and it is not shorted on the blue wire plug the climate control panel back in with no sensor value returns to 22699 at this point I’m thinking the issue is with the climate control panel any thoughts?
1037532
 

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Is the right heat exchanger sensor working correctly? Have you checked it for its resistance?

Take a look at the functional description of the sensor:

Heat exchanger sensor, right
The right-hand heating heat exchanger temperature sensor is a component of the integrated heating / air-conditioning system with left‐right separation. The sensor measures the delivery temperature directly at the delivery side of the heat exchanger for heating system on the passenger's side.
A total of 2 heating heat exchanger temperature sensors are installed (on the delivery side of the heat exchanger for heating system to the driver's side and on the delivery side to the passenger's side). The 2 heating heat exchanger temperature sensors are identical components.
The IHKA control unit (IHKA stands for "integrated automatic heating and air conditioning system") evaluates the signal from the right-hand heating heat exchanger temperature sensor. The IHKA control unit uses this message to regulate the front right stratifying-flap motor.
Functional description
The heating heat exchanger temperature sensor is a hot conductor or NTC resistor (”NTC” stands for ”Negative Temperature Coefficient”). NTC resistors can convert the ”temperature” value into a ”resistance” value, which can then be evaluated electronically. The conductive materials in the NTC resistor conduct current better at high temperatures than at low temperatures. That means: The higher the temperature, the lower the resistance.


ItemExplanationItemExplanation
1Heat exchanger temperature sensor2two‐pin plug connection
Structure and inner electrical connection
The heating heat exchanger temperature sensor is supplied with 5 Volts by the IHKA control unit. To balance inner temperature effects, the NTC resistor is operated at low current. This means that the external ambient temperature is decisive for the resistance value.



ItemExplanation
1NTC resistor
Pin assignments

PinExplanation
5 VSupply voltage
Terminal 31ETerminal 31 E, electronics earth (ground)
Specifications and characteristic curve
Every temperature change at the NTC resistor leads to a change in the voltage signal. The evaluation takes place in the IHKA control unit.



ItemExplanation
1Temperature in degrees Celsius (°C)
2Characteristic curve for hot conductor
3Resistance in kiloohms (kΩ)
Observe the following setpoint values for the heating heat exchanger temperature sensor:

VariableValue
Supply voltage5 V
Temperature range-40 to 85 deg C
Resistance range (measuring range)1.2 to 100 kΩ
Diagnosis instructions
Failure of the component:

If the right heating heat exchanger temperature sensor fails, the following behaviour is to be expected:
  • Fault entry in the IHKA control unit
  • Substitute value of IHKA control unit: 55 °C
 

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Discussion Starter · #3 ·
Is the right heat exchanger sensor working correctly? Have you checked it for its resistance?

Take a look at the functional description of the sensor:

Heat exchanger sensor, right
The right-hand heating heat exchanger temperature sensor is a component of the integrated heating / air-conditioning system with left‐right separation. The sensor measures the delivery temperature directly at the delivery side of the heat exchanger for heating system on the passenger's side.
A total of 2 heating heat exchanger temperature sensors are installed (on the delivery side of the heat exchanger for heating system to the driver's side and on the delivery side to the passenger's side). The 2 heating heat exchanger temperature sensors are identical components.
The IHKA control unit (IHKA stands for "integrated automatic heating and air conditioning system") evaluates the signal from the right-hand heating heat exchanger temperature sensor. The IHKA control unit uses this message to regulate the front right stratifying-flap motor.
Functional description
The heating heat exchanger temperature sensor is a hot conductor or NTC resistor (”NTC” stands for ”Negative Temperature Coefficient”). NTC resistors can convert the ”temperature” value into a ”resistance” value, which can then be evaluated electronically. The conductive materials in the NTC resistor conduct current better at high temperatures than at low temperatures. That means: The higher the temperature, the lower the resistance.


ItemExplanationItemExplanation
1Heat exchanger temperature sensor2two‐pin plug connection
Structure and inner electrical connection
The heating heat exchanger temperature sensor is supplied with 5 Volts by the IHKA control unit. To balance inner temperature effects, the NTC resistor is operated at low current. This means that the external ambient temperature is decisive for the resistance value.



ItemExplanation
1NTC resistor
Pin assignments

PinExplanation
5 VSupply voltage
Terminal 31ETerminal 31 E, electronics earth (ground)
Specifications and characteristic curve
Every temperature change at the NTC resistor leads to a change in the voltage signal. The evaluation takes place in the IHKA control unit.



ItemExplanation
1Temperature in degrees Celsius (°C)
2Characteristic curve for hot conductor
3Resistance in kiloohms (kΩ)
Observe the following setpoint values for the heating heat exchanger temperature sensor:

VariableValue
Supply voltage5 V
Temperature range-40 to 85 deg C
Resistance range (measuring range)1.2 to 100 kΩ
Diagnosis instructions
Failure of the component:

If the right heating heat exchanger temperature sensor fails, the following behaviour is to be expected:
  • Fault entry in the IHKA control unit
  • Substitute value of IHKA control unit: 55 °C
I replaced it,same value, unplugged it at the sensor same value, unplugged it from the IHKA same value. Only way I can get a value less than 22000f is to unplug the opposite connector. Then all values go to 32f.
 

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Discussion Starter · #4 ·
I replaced it,same value, unplugged it at the sensor same value, unplugged it from the IHKA same value. Only way I can get a value less than 22000f is to unplug the opposite connector. Then all values go to 32f.
Also swapped left to right same result.
Thanks for the reply.
 

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When you swapped right and left sensors, did the problem move to the left, or stayed on the right sensor?

Have you tested the 5V supply of the sensor from IHKA?
 

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Discussion Starter · #6 ·
When you swapped right and left sensors, did the problem move to the left, or stayed on the right sensor?

Have you tested the 5V supply of the sensor from IHKA?
The problem stays on the right, yes I have 5v on the right. When I remove the black connector the value stays the same. When I remove the blue connector the value goes to 32.
My assumption is the Blue wire from the right heat exchanger is the blue wire on the black connector. So Black connector signal in climate control.
When I unplug the Blue connector the value goes to 32f. Seems as though the blue connector communicates with the ECU.
Questions
Is the Black connector input to climate control (IHKA)
Is the blue connector output to ECU.
it appears as though the climate control is generating the 22000 value.
1037635
 

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I will explain the wiring:

Sensor is connected to pin 12 (blue/black wire) of A95*1B connector of the Heating/air condition control unit:

1034678



and the other end of the cable is at the sensor, connector B9*1B, pin 1:

1034679



pin 2 of this connector is the ground and it is connected to X224*1V:

1034680


Communication with the rest of the car is via LIN bus which connects to pin 18 (white/brown) of A95*2B connector. Pin 1 (red/green) of A95*2B is the fuse.

Check the sensor connection for a good ground. Next step would be a new control unit, but a so specific fail makes me hard to believe the whole unit has failed...
 

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Discussion Starter · #8 ·
I will explain the wiring:

Sensor is connected to pin 12 (blue/black wire) of A95*1B connector of the Heating/air condition control unit:

1034678



and the other end of the cable is at the sensor, connector B9*1B, pin 1:

1034679



pin 2 of this connector is the ground and it is connected to X224*1V:

1034680


Communication with the rest of the car is via LIN bus which connects to pin 18 (white/brown) of A95*2B connector. Pin 1 (red/green) of A95*2B is the fuse.

Check the sensor connection for a good ground. Next step would be a new control unit, but a so specific fail makes me hard to believe the whole unit has failed...
Thanks, yes the value read dose not change if I unplug A95*1B. It only changes if I unplug A95*2B. I found a control unit for $50 hoping to pick it up tomorrow.
I guess there is always the possibility that it is in the harness from A95*2B and either the short or cross connect only shows with it plugged in.
this is a salvage car and many airbags and airbag controllers have been replaced.
Thank you for the help.
 

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Discussion Starter · #9 ·
Thanks, yes the value read dose not change if I unplug A95*1B. It only changes if I unplug A95*2B. I found a control unit for $50 hoping to pick it up tomorrow.
I guess there is always the possibility that it is in the harness from A95*2B and either the short or cross connect only shows with it plugged in.
this is a salvage car and many airbags and airbag controllers have been replaced.
Thank you for the help.
 

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Discussion Starter · #10 ·
I probably said this elsewhere, I’m trying to track down inconsistent ac. When the ac works it will freeze you out with a 25lb low side and 250 lb high side. Sometimes it will work perfectly for 8 hours after starts and stops. Then it will blow warm with 60lb low and 120lb high pressure.
looking to eliminate all errors and maybe both are caused by the Climate control. At this point it’s worth $50 for me to try and rule out the controller. I have replaced the ac pressure sensor.
 

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Discussion Starter · #11 ·
Ok installed the climate control unit. It did not solve the 22669f on the right temp sensor. However it did solve my ac situation. All phases of AC/ heat appear to work fine now. So the system must be substituting 55f for the 22669f.
Another data point is that the temperature goes to 32f when the ignition is turned off. Makes me think it’s voltage noise on the way to the Lin bus, does that make sense.
it is 75f outside now rather than the 82f last week.
 

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Discussion Starter · #15 ·
I tried multiple pins to probe B9*1B and as you thought I could not get a ground. Ohm meter didn’t move. How ugly would it be if I spliced to body ground or spliced a ground from B16*1B?
 
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