[SSW]

Had a weird experience w/the AC the other day.

The car (black) had been sitting in the hot sun for awhile (about an hour at 90+) and when I drove back home, the driver's side vents were blowing HOT (really hot) and the passenger side vents were blowing COLD at the same time. Both sides were set at 68 degrees.

This has never happened before. However, I have noticed that the AC tends to blow warmer (not hot) on the driver's side than the passenger side AND that the AC has difficulty getting the car cold after it's been sitting in the sun.

One shop said that the problem might be caused by a computer malfunction of some sort causing the electronic vent flap diverting the heat/cold to malfunction (and/or a mechanical malfunctioning of the vent flap itself). Removing/replacing the flap requires removal of the entire dash -- WTF!!!

Scheduled a visit to the shop to diagnose and fix the problem but, after the car cooled overnight, the problem went away. No point bringing in the car for fix the problem if it the problem's not replicable.

Anyway, has anyone else experienced this problem and/or does anyone have any idea what the problem might be and how to fix it? If so, please let me know.

Thanks!

[Efthreeoh]

Based on descrition of the HVAC system provided in the Bentley service manual, I'm not sure the shop is 100% correct. The HVAC flaps are controlled by 7 identical servomotors. From what I understand according to the Bentley, all seven are accessable without removing the dash.

[SSW]

Originally Posted by Efthreeoh

Based on descrition of the HVAC system provided in the Bentley service manual, I'm not sure the shop is 100% correct. The HVAC flaps are controlled by 7 identical servomotors. From what I understand according to the Bentley, all seven are accessable without removing the dash.

Well that's good to know -- that you don't have to remove the dash to access the servos.

Now, the question is why the heck was the HVAC blowing both HOT and COLD at the same time?

Love to hear an answer to THAT question!

[Tom K.]

Originally Posted by SSW

Well that's good to know -- that you don't have to remove the dash to access the servos.

Now, the question is why the heck was the HVAC blowing both HOT and COLD at the same time?

Love to hear an answer to THAT question!

On my E46, that was a symptom of an improperly charged system. The first time it happened, a number of leaks were repaired. When the problem resurfaced 4 years later, the refrigerant level was found to be slightly low which was easily remedied.

Tom

[Efthreeoh]

Originally Posted by SSW

Well that's good to know -- that you don't have to remove the dash to access the servos.

Now, the question is why the heck was the HVAC blowing both HOT and COLD at the same time?

Love to hear an answer to THAT question!

If the logic is messed up by a faulty actuator, it could run hot and cold at the same time. It has a split system.

[SSW]

Originally Posted by Tom K.

On my E46, that was a symptom of an improperly charged system. The first time it happened, a number of leaks were repaired. When the problem resurfaced 4 years later, the refrigerant level was found to be slightly low which was easily remedied.

Originally Posted by Efthreeoh

If the logic is messed up by a faulty actuator, it could run hot and cold at the same time. It has a split system.

Thanks for the tips.

Between the 2, the 1st seems the easier to diagnose. So, I'll take it to a local shop that I trust (instead of the Stealership) to see if they can detect any leaks. Otherwise, I'll just leave it alone until it fails completely and does it all the time so that it can be properly diagnosed and repaired or (better yet) sell the car before then.

[SSW]

Had car in shop to replace the water pump/thermostat and asked them to check the AC. Only 1/2 lb in a 1 1/2 lb system. Told them to charge it up. Will see if that solves the problem or not.

[SSW]

Had car in shop to replace the water pump/thermostat and asked them to check the AC. Only 1/2 lb in a 1 1/2 lb system. Told them to charge it up. Will see if that solves the problem or not.

Update:

Just got the car back and it's blowing REALLY cold!

Mechanic said that freon will bleed out via osmosis over time and that passenger side always seems to blow little colder than the driver's side in a dual AC system BUT that the hot/cold problem that I was having was not freon related and, if it comes back, it has to do w/a sensor or actuator and, if it's the actuator, the entire dash has to come out to fix it.

Hopefully, that will never be necessary.