External temperature sensor not working.

[Chasottmg4]

Because my MG4 Ambient external temperature sensor was not working, I was having issues with only getting the heating to work when set to max and the rest of the time cooling was not adjustable, it was very cold.
I ordered a replacement sensor. This new sensor was showing the temperature on the high side.
So I measured the amount of kΩ it was showing and added a resistor to bring the temperature down to what the outside temperature actually was. This has worked really well, and my aircon and heating work accurately.
Saves me having to endure a garage.

 

[OriginalBigAl]

Because my MG4 Ambient external temperature sensor was not working, I was having issues with only getting the heating to work when set to max and the rest of the time cooling was not adjustable, it was very cold.
I ordered a replacement sensor. This new sensor was showing the temperature on the high side.
So I measured the amount of kΩ it was showing and added a resistor to bring the temperature down to what the outside temperature actually was. This has worked really well, and my aircon and heating work accurately.
Saves me having to endure a garage.

More details please, schematics etc, strip it out then refit with a Youtube video !

 

[mg4]

While testing out fast charging noticed that if I preheat the battery and start a charge then the ambient temperature sensor would almost follow the battery temperature. Might be the same thing? For me starting a charge at 16 degrees celsius and having the temp skyrocket to 41 degrees celsius was a bit of a shock. I have no idea where the sensor is placed, but I can imagine that if it reports 41 and the target is 22 it will blow ice cold air to cool quickly.

 

[siteguru]

The external temperature sensor is on the front of the car, in the section where the front vents are fixed. (i.e. on the front-left on UK cars, front-right as you look at the front of the car).

 

[Chasottmg4]

More details please, schematics etc, strip it out then refit with a Youtube video !

I will try to show some of it, later in the week.

 

[Chasottmg4]

The external temperature sensor is on the front of the car, in the section where the front vents are fixed. (i.e. on the front-left on UK cars, front-right as you look at the front of the car).

Ireland's cars are the same as UK.

 

[siteguru]

Ireland's cars are the same as UK.

Yes, but the person I replied to is from The Netherlands. I'd be surprised if the sensor was in a different position on LHD cars vs our RHD cars, but you never know.

 

[mg4]

For my side question, it would be weird if the sensor shifts and then starts measuring some exhaust. Still cannot figure out why the ambient temp showed 41 when it was 16 celsius. But if my situation is different, let's park it.

 

[Chasottmg4]

Yes, but the person I replied to is from The Netherlands. I'd be surprised if the sensor was in a different position on LHD cars vs our RHD cars, but you never know.

For my side question, it would be weird if the sensor shifts and then starts measuring some exhaust. Still cannot figure out why the ambient temp showed 41 when it was 16 celsius. But if my situation is different, let's park it.

It's interesting. Is the temperature correct if you are not using the pre-heater?

 

[mg4]

It's interesting. Is the temperature correct if you are not using the pre-heater?

I will need to check it more aware, but last 2 DCFCs were without a preheat and i did not notice the temp spike. But maybe i did not pay attention.

 

[JonnyG]

For my side question, it would be weird if the sensor shifts and then starts measuring some exhaust. Still cannot figure out why the ambient temp showed 41 when it was 16 celsius. But if my situation is different, let's park it.

Were you parked with the sensor in the direct sun perhaps ?

I know when I've been drying my front grille in Winter with heated air from a car dryer the flaps have suddenly opened which took me by surprise !. (BTW the car was turned on to heat up inside)

 

[mg4]

Were you parked with the sensor in the direct sun perhaps ?

I know when I've been drying my front grille in Winter with heated air from a car dryer the flaps have suddenly opened which took me by surprise !. (BTW the car was turned on to heat up inside)

The nose of the car was pointed to the sun, but that would be so weird. I don't focus on driving away from it

 

[JonnyG]

The nose of the car was pointed to the sun, but that would be so weird. I don't focus on driving away from it

Your post above #3 said the temp rose while you were DC charging (so presumably parked up). I'm just suggesting that if the front sensor was in the sun while you were charging it may have got pretty hot from that, especially with all the black trim surrounding the sensor, and nothing to do with battery temp.

Once you are actually driving again at any reasonable speed the sensor will be cooled by the air flow (either into or away from the sun).

 

[mg4]

It could be, in that case my remarks have nothing to do with the OP. If i notice it again i will start a new thread.

I am still curious about the potential fix the OP mentioned and a guide around it.