Ac Problem... No Heat
 

Guys, I do believe that when you put the car at 90^ that the car should put out hot air instead of cold right.... so why does'nt mine do that. i've heard someone else had this problem. Did a search but didnt find anything. I just want some warm air in the morning cuz it's getting cold down here in the morning in MIA. Thanks.

3 Quick thoughts with your problem:

1) Does the temp. gauge register that the car is heating up to normal operating temp.? If not, and the car is blowing cold air when set at 90 degrees, then the thermostat might be stuck open, such that the coolant never gets appropriately heated in the engine block. You would need replacement of the thermostat which should be a pretty straightforward job (although I wouldn't do it myself).

2) Obstruction in the heater core behind the dash, but if this is happening, the engine would normally overheat.

3) Insufficient coolant in the radiator, but this would also be expected to result in engine overheating.

I think it's worse than that. Many of us deal with a control unit that requires users to adjust the temp all the way to 90 to get any heat at all. this is not normal and a sign of a faulty control unit. With this being a common problem w/the TL(along w/every other common problem ie losing headlight seals,tranny,sunroof,warped rotors,radio controls on wheel,cd changer,seat heaters ect...)my first guess would be that yours went completly out.

:agree: I have to crank the heat to 90 for it to realize that I actually want hot air. I'm in an 03 as well.

I know this thread is REALLY REALLY old, but, I just got an '03 TL Base, 5AT, 229,000 miles (I know OMG HIGH MILES!!! But I paid 3200 for it, so its all good). The A/C vents are giving me very little flow, I had a 2000 Accord and it had 4x the flow, it seemed like. Also, the heater doesn't really like to give me heat, even with it set all the way to 90. I just replaced the cabin filter, as the one that was in there was so dirty and stiff it felt like it was gonna crack in half, but I have had almost zero improvement. Can anybody help me? I'm new to the luxury scene, and have no idea what I'm working with. Thanks in advance!

Poor air flow from the vents could be caused by a faulty blower motor resistor pack. The low heat may be due to a malfunctioning heater inlet valve or perhaps a sticky T-stat.