[njjoe]

oregon2-

Was it frost on the outside of the glass or moisture on the inside of the glass?

-njjoe

 

[njjoe]

It was moisture on inside of glass- not cold enough (45 degrees) for frost.

Difficulty in removing moisture from the inside of the glass can be attributed to one of two things: 1) The HVAC is incorrectly set to RECIRCULATE, when it should be set to FRESH air; and/or 2) the A/C was not enabled.

Next time you encounter those conditions make sure the HVAC is set for FRESH air and the A/C light is illuminated.

That should do the trick.

-njjoe

 

[njjoe]

Checked operation - turn on front defrost - A/C compressor and electric fan come on for 5 seconds - then shuts off for 15 seconds- and continues to repeat this cycle. Is that NORMAL ??

O2-

Yes, that is normal. The A/C compressor will cycle to maintain a maximum temperature in the evaporator core. If it was to run continuously you would risk freezing-up the evaporator coils.

-njjoe

 

[njjoe]

That doesn't sound normal - it should be on continuously when the defog is on.

E-

No, it should not be on continuously.

Just because the compressor is not running does not mean that the A/C system is not cooling and dehumidifying the air. When the compressor cycles off there is still a cooling effect in the evaporator core because 1) the expansion valve continues to meter high-pressure liquid freon in to the lower-pressure core, and 2) the relatively cold evaporator acts as a heat sink and continues to absorb heat from the air.

-njjoe

 

[njjoe]

As the car ages the compressor will run more due to leaks in the system developing. Then it will evendutally come to a point when the compressor is on all the time and you get nothing out of.

That will be a sad day for the MO.

G-

With any luck, that will coincide with the day you are trading in the MO for another.

-njjoe

 

[njjoe]

O2-

Since nothing else seems to work, I am going for the "longshot".

If the A/C condensate drains were blocked, then it is possible you would have a pool of water in the HVAC airbox. The airflow would pick up moisture from the entrained water and it would condense on the windshield. So while you are defogging the glass the HVAC system is adding to the problem.

I had this happen on a previous car, but I am not sure if the configuration of the MO's airbox would support such a condition.

When you park the car after driving with the A/C on do you see a puddle of water form under the car in the area of the front passenger-side footwell? If you do, then this longshot idea "doesn't hold water". However, if there is no water under the car, then we may be on to something.

-njjoe

 

[njjoe]

Originally posted by Tyler_Canada
Regarding recirculate mode, that is definitely NOT on in defrost mode (not possible, the intake for the recirculate is the defrost vents)

Tyler_Canada-

You are mis-informed. The intake for the recirculated air is not the defrost vents. The intake is behind the dash on the passenger-side of the MO.

-njjoe