Defroster???

[chicayne]

I just bought a 1996 318ti and ever since I got it I have had problems with the defroster. The heater and blower work fine but the windows fog up all the time and the only way that I can keep them from fogging up is by using the A/C. If the A/C is not on it will not defrost my widows but, if it is on, weather or not it is all the way on cold or all the way on hot does not matter. It is weird because with the A/C on and the temperature selector all the way on hot the air coming out is hotter that with the A/C off and the temperature selector all the way on cold. It makes no sense. It wouldn't be a problem but I am about to move back to Wisconsin and I don't feel like driving around in the middle of the winter with the A/C on because my windows fog up. I have tried everything that I could think of, I even resorted to Rain-X anti-fog and it didn't work at all. Thank you for the help, I appreciate it.

[dave45056]

This might sound like a stupid question, but are you recirculating the air?

[zboot]

This might also sound a little stupid but. . . I'm not sure I understand what you mean by AC on. You mean with the fan on (say at 3 or 4) and the AC button depressed? Without the fans blowing. . . I don't see how you'd expect it to defrost.

[chicayne]

No I am not recirculating the air and, yes with the fans blowing and the A/C button depressed.

[zboot]

Ok, and I assume you have the output set to defrost and not blowing at your feet or something. Well, if your hvac system works normally, ie you get heat and cool w/o using the AC button. . . then it could just be that the relative temperatures and pressures inside and outside your car are doing a terrific job resisting your attempts to defrost it.

[aceyx]

You're supposed to have the AC on while defrosting the windshield. You need dry air to get rid of that moisture.

You're also supposed to have circulation OFF.

[zboot]

Here is what it says in the manual:

To defrost windshield and door windows

Set rotary fan selector for the air-flow rate to position 4.
Turn rotary temperature selector all the way to the right (red).
Set rotary selector for air distribution to the position [defrost].


Switch on the rear window heater to defrost the rear window.

[bbbmw]

Check the carpets for dampness - there may be a water leak into the cabin, which would increase interior humidity. Also, have you changed the cabin filters? Perhaps they are clogged. Monitor the coolant level to rule out a leaking heater core. Good luck.