Date registered: Apr 2019
Vehicle: 1999 E320 Wagon: 130,000 miles
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Quoted: 8 Post(s)
AC Fan Speed Starts/Stops
The air conditioner fan on my 1999 E320 Wagon (base, not 4Matic) runs at high speed when car is idling or the power load is reduced. Once I accelerate or if a slight positive incline puts a load on the engine, the two side vents seem to not be affected, however air volume from the two central vents is greatly diminished, nearly to no air. The fan noise stops as well. Once I start to slow down or load is reduced by road conditions, the fan returns to full speed. Is this normal; does the AC fan stop when the motor load is increased? I’ve added the information from the AC codes in case they may be useful. I followed directions as below:
Preparation for Test
2. Ignition: ON
3. Press Auto .
4. Set both temperature selectors to 72°F.
5. Press Rest for > 5 secs.
6. The left display will alternately show the number 1 and the in-car temperature (e.g. 72°F)
7. By pressing Auto the next highest test step is displayed (see table).
8. Press Rest to end test program.
And copied the sensor readings as shown in attachment. Conditions for readings are below:
1. Before the car was started; has not been started in 2-3 days; key in position 2.
2. About 1-2 minutes after number 1 above; car idling.
3. After driving car 10-15 minutes in city traffic; car idling;
4. Turned car off.
5. After sitting in hot parking lot for 10-15 minutes; key in position 2.
6. After driving 10-15 minutes, car traveling around 40 mph.
Thanks for your help.