My '99 ML320 is a great vehicle but I have one big beef:
When I purchased it I accepted that it did not have automatic climate control. Now I believe that it doesn't have any climate control.
The air flow to the feet in both the front and rear seats seems totally inadequate. While in cold weather, say 20 deg.F, Everyones feet freeze. When the outside temperature is 60deg F I have to turn on the air conditioning.
I have had it to the dealer twice and they say there is nothing wrong with it. I have to conclude that it is a faulty design if that is true.
I have not been able to get any specs on air flows, velocities or the minimum delta T on the heater (temp. selector turned to max. cool and a/c off.)
Any help on this topic would be appreciated.

Joe M

Joe,
Looks like Mercedes knows about the lack of heat output for the drivers side!! There is a special duct being tested to correct the problem. The part # for the modification is
163-680-01-17, also your dealer should have information about this change; MB-net 109.
Hope this helps you!!

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH

The response on the air flow is useful. Any suggestions on the heat problem.

If the outside temperature is above 60 deg F., I must use my airconditioner to keep the inside temperature from rising to uncomfortable levels. This might be 85 deg. F.or so.

Tks.
Joe McMullen

Unlike all other Mercedes, the ML doesnt have a heater valve to keep water from flowing thru the heater core!! The heater box has flaps that are supposed to keep the heat from getting to you in the fresh air & a/c modes, somewhat like domestic cars. Guess it's not working as well as designed, haven't seen anything about this problem yet.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH

I can't tell you how much I appreciate the advice I am getting from you guys.
It really is a pleasure to get feedback from the ASE Master Technicians.

Thanks.
Joe McMullen

Gee thanks, a lot people don't realize how difficult new cars are to diagnose.
I'm sure that someone can come up with a heater valve that can cut off the flow of water thru the heater when you dont want heat.