Just wondering:

In a 2000 ML when you have the temperature knob set in the middle to get an in between temperature, do that just open (or partially open a value) to let hot water in from the engine to blend with the a/c cold air to get medium air.

Because on my 92 honda accord the temperature knob is connected to a value that open and close to allow hot water in.

Or is it a little more intelligent that? Where the electronic logic know to turn on the a/c at a higher cabin temperature??

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Silver Honda Accord, 2006
Silver G500, 2003
Silver SLK-320, 2002
Black ML-320, 2000
Bule Porsche 993 Targa , 1997
Silver Merkur XR4Ti, 1987

Denso designed & built that system to a PRICE...no heater valve..has a control unit (amplifier) that evaluates the in-car temp & position of the temp wheel & opens or closes (in stages) the blend air door...seems to work good for a basic system..went to A/C/C in 2002 with dual controls.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

So on a mild day. if the temperature wheel is set to a mid temp setting. The system will control temperature by turning the a/c on and off to control the temperature instead of mixing hot air from the engin?


This seem to be a dumb questions. But like I said the temp wheel on my 92 honda get connected directely to a value that opens and close to allow coolent from the engin to the heater heat exchanger.

__________________
Silver Honda Accord, 2006
Silver G500, 2003
Silver SLK-320, 2002
Black ML-320, 2000
Bule Porsche 993 Targa , 1997
Silver Merkur XR4Ti, 1987

The compressor on 1996 & later Benz rarely cycle once the system is on...due to variable capacity A/C compressors. So lets say the outside temp is 70F & you set the temp for a comfortable temp then the blend air door works with the in-car temp sensor blending fresh air, heated air & cool air to achieve the desired setting...

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

So in your example here. if the inside cabin temperature is below 70 deg, the the controler will blend in a little heated air with the outside air to get the desire temp (the compressor is off in this case) until the desire temperature is met.


And if the inside cabine temperature is above 70 deg, the controler will belend in a little cool air cooled from the compressor with the outside air to get the desire temp (hot air from the heater is turned off) until the desire temperature is met.

And if the combine temperature is right at 70 then the compressor and the heater is off and you are only getting outside air.


So, for a mercedes it is always most efficient to set the temperature wheel to a mild temperature??

__________________
Silver Honda Accord, 2006
Silver G500, 2003
Silver SLK-320, 2002
Black ML-320, 2000
Bule Porsche 993 Targa , 1997
Silver Merkur XR4Ti, 1987

blau:

The 2000 ML's climate controls are semi-automatic. If you look in the opening to the left of the MCS, you'll see a thermistor that measures cabin temp.

I've left my temp dial knob at the 11 o'clock since I bought the car 6 yrs ago. Think of the dial as an uncalibrated temp knob instead of cool (blue) vs. hot (red). You have to turn on the A/C yourself and remember to close the middle vents in the winter to get heat to your feet. Other than that, it works much better than the knobs you think it looks like :-)

In Dallas, Texas -- I need the cooling air most of the time. I may have used the "heater" in my ML a couple of times in several years. I also like to filter the air here because of the pollen and other stuff in the surrounding atmosphere, so I normally have the dial on Blue/Cool and the fan on 2 or 3 -- sometimes using the Recirculating setting when I want to cool it down really fast after starting on a 100 degree day. My 68 230S does not have a/c, so the heat is all that can be used and my 89 and 92 Mercs have the dial up settings for climate control ... again, a little different in the hot, hot climate of Texas and other parts of the southern U.S.

__________________
Ben Harrison Carter
1999 Mercedes ML320 87K
1992 Mercedes 300CE 89K
1995 Corvette 29K -- Sold Dec 09
1989 Mercedes 420SEL 99K -- (Sold 4/08)
1968 Mercedes 230S (106K) (Sold 9/06))
1976 Mercedes 450SEL 130K (Just sold - 06)
1961 Mercedes 220Sb (sold years ago)