Air Con External Air Temp Sensor Location? Aux water pump location?

[KarlosG]

Hi, just trying to sort a few A/C issues...

INPA is showing -45c for the A/C external air temp sensor (not the ambient air temp sensor for the dash, that's working fine) does anyone know where it is please?
Also my auxiliary water pump is showing a "short to ground" error, does anyone know where i might find that too please?

Thanks,
Karl

[Sabreslight]

on the facelifts, the Ambient Air temp sensor is located on the passenger side duct panel under the front bumper directly in front of the tire. the other temp sensor is on the evaporator.

[chrisn7]

The sensor on the dash is the 'Cabin' temperature sensor, the 'Ambient' is correctly described above.

The auxiliary water pump is mounted under the heater water valves on the right suspension turret as you look into the engine.

[tjpike]

The sensor on the dash is the 'Cabin' temperature sensor, the 'Ambient' is correctly described above.

The auxiliary water pump is mounted under the heater water valves on the right suspension turret as you look into the engine.

I'm not a 100% sure about this as you have a 728i and they were not offered here in the states, but I believe your aux water pump is located on the radiator fan shroud on the bottom just like on the e39 528i.

[KarlosG]

on the facelifts, the Ambient Air temp sensor is located on the passenger side duct panel under the front bumper directly in front of the tire. the other temp sensor is on the evaporator.

The sensor on the dash is the 'Cabin' temperature sensor, the 'Ambient' is correctly described above.

The auxiliary water pump is mounted under the heater water valves on the right suspension turret as you look into the engine.

Thanks fella's but I'm a little confused still.
I thought the ambient/outside temp sensor under the bumper near the wheel was just for the temperature displayed on the dash? This reads correctly but my A/C external temp reading in INPA is what's showing -45c.

- - - Updated - - -

30lmhjo.jpg

[KarlosG]

Bump.

[Timm]

From the WDS, the Air Conditioning uses the same sensor as the MID, B21. Why INPA reports a different temperature goodness only knows - but INPA does have form for some misreporting....

[KarlosG]

Oh does it, that's not helpful then... I have no way of knowing if the ECU is actually seeing the correct temp or not.

[Qsilver7]

You can see in the BMW data below about analog signals...the OUTSIDE AIR TEMP sensor (aka AMBIENT AIR TEMP sensor) are the same thing...and that this outside/ambient temp sensor sends data to the IKE (instrument cluster) which also shares this data with other systems that require it. The IHKA is one of them...because it uses several different ambient/outside air temps to run or shut down some of its features.

If you read the AUTO CLIMATE SYSTEM details in the owners manual...you will see multiple air temperatures mentioned that the IHKA uses to determine certain functions. The only way the IHKA knows what the ambient/outside temperature is through the data that sensor sends to the IKE:

[KarlosG]

Ok there's definitely only the one sensor then, thanks for that.
So any idea why INPA reports such a low temp but the IKE show accurate? Also my MAX button only seems to function on hot days here in the UK (20C+), I know that is disabled if the temp is below a certain threshold too (5C IIRC) also pointing to the ECU seeing a low temp?

[Mayorchuck]

Hi, just trying to sort a few A/C issues...

INPA is showing -45c for the A/C external air temp sensor (not the ambient air temp sensor for the dash, that's working fine) does anyone know where it is please?
Also my auxiliary water pump is showing a "short to ground" error, does anyone know where i might find that too please?

Thanks,
Karl

My aux water pump has shown a short to ground error for 10 years. Never had an issue with it.

https://www.newtis.info/tisv2/a/en/e38-728i-lim/Uve6iSj

[Qsilver7]

Ok there's definitely only the one sensor then, thanks for that.

1. So any idea why INPA reports such a low temp but the IKE show accurate?
2. Also my MAX button only seems to function on hot days here in the UK (20C+), I know that is disabled if the temp is below a certain threshold too (5C IIRC) also pointing to the ECU seeing a low temp?

#1 - I don't have an answer.

#2 - The MAX button is a preprogrammed IHKA setting for when ambient temps are hot. See the info below as to the TWO STAGE functions of the MAX button and what the ambient temperature needs to be for either of the two settings to operate (5°C & 16°C)...or heat the interior after the engine has been turned off (RESIDUAL HEAT function can be activated below 15° C):