In putting the heat on, on a cold day, the temperature at around 70-72 F, the heat usually comes out strong. Sometimes on a short trip I will stop somewhere and shutoff the car. The temperature will be cold even when the car is warmed up. So I crank it p to HI and it finally gets hot, But then I bring it back to 72 and its lukewarm. Outside temp: 0-1 Degrees Celcius.