Hyundai Repair: XG300 01 Ambient air temp sensor, deg c, ambient temp

Question
I have trouble gettng warm air from the heater even on cold days. The ambient air temp reading is often near 50 deg C (110F) so on auto setting I get air conditioning rather than heat. Do you think the ambient temp sensor may be the problem? Can you offer instructions on how to get to it, test and replace it? Thx

Answer
Your problem can indeed be caused by a faulty ambient temperature reading.  The ambient temperature sensor is located behind the bumper/grille and in front of the condensor.  You'll need to check its resistance if you wish to verify the sensor is defective.  Below is a resistance chart:

32 degrees F = 95k Ohms
50 degrees F = 58k Ohms
68 degrees F = 37k Ohms
86 degrees F = 27k Ohms

The easiest way to do this is probably to take it off the car and take it inside and let it sit overnight.  Presuming your house temperature is close to 68 degrees F, check it's resistance the next morning and verify it's within a couple thousand Ohms of 37k.