dougpark714

The manual clearly states that you can change the rear temp by pushing "rear off" and changing the temp with right dial. But this does not work. Pushing the "rear off" just turns off the rear. Can someone with 2009+ with 3 zone try this? The 2009+ model climate control changed for us models. Thx

fs1013

Interesting you raise this because I tried the same thing yesterday and had the same result. I may ask the dealer to verify it and will post it if I get an answer.

dougpark714

Thx hope we're doing something wrong. It would be a pain if you can only set the temp from the rear.

Also, every time I change the temp from the rear control, it resets to 72 when the car restarts. 70 is a better temp (for our the kids). I hope there's a way to set the temp so the car remembers. The front settings are stored.

fs1013

OK, ask my sales rep last week and he spent 30 minutes in one of the GL550s they got and got back to me this morning.

Same as us, he couldn't control the rear temperature from the font. He believes the button does only as what it suggests - "REAR OFF".

I went and read the online manual again and I think the link I have is for the European version. The climate control panel shown in the manual looks more modern and functional to me, and I think the Canadian version is the same. Not only that it gets you the ability to control the rear temperature from the front, You can also change it to "MONO" mode which is to set the whole compartment as one zone, I think. When I first saw the difference, I thought it's for the different taste of Americans. Now I start to think we got the stripped-down version in the US. Because I don't think you need to change the design of the whole panel to control and show from Celsius to Fahrenheit.

Mine however does remember the temperature settings at the rear control. I just tested it again, started the car, changed the temperature to 70, turned off the ignition, wait for 3 minutes, started it again and it remained at 70. I even did it again and set it at 60 and it remembered. My sales rep confirms the same on his tested GL550 as well. So you may want to check it again.

dougpark714

Check on page 142 on the US manual, it shows instructions to change the rear temp for both US and Canadian models. You're right the Canadian model comes with a different climate control which has a dedicated button for changing the rear temp. For the US model, it says to push the "rear off" and change the rear temp using he right dial which I agree makes no sense. Seems like an oversight on MB's part. Or we're doing something wrong.

I'll test the rear temp again. Thanks for the tip.

fs1013

Yes I know what you are saying. It's page 187 in my MY2010 owner's manual under the section "Rear temperature with front climate control panel". And it separates into "USA only" and "Canada only" sections so there is no confusion it should work for our US model. It says clearly how to make temperature adjustment as you mentioned in your first post. But it doesn't work. I do hope we are doing something wrong. Anyone got this to work?

I will ask my SA to find out and maybe to check with MBUSA and get us a confirmation.

fs1013

Thought I should come back and update. My SA responded almost one month ago as below:

"When you press REAR/OFF, you are actually making the climate control a 2 zone system: drivers zone and a zone for all other passengers (RF and rear). The climate control will then automatically try to keep the temperature for the rear and the passenger front seat whatever temp you have set it to."

I argued and explained to her that's not what the manual says. She said she would go play with one and let me know but I haven't heard her back. I will remind her again and see what's going to happen.

I however notice lately it doesn't seem to hold the set temperature of the rear control for good as I thought it did. There seems to be a timer to reset the temperature back to 72 after the vehicle is turned off for some predetermined time. I don't know the exact time. All I know is it remembers the settings still within 5 minutes after the engine is turned off, and it resets back to 72 overnight. Will ask the question to my SA as well.

dougpark714

Yes I noticed the rear temp reverts to 72 after some preset time. I usually decrease the temp to 70 by feel. Really annoying.

When I turn off the rear I don't feel any air in the rear vents so I don't think the sa is right. I wonder if there's a way to retrofit the older unit which is standard in Canada. The canada control has a rear temp button. Should be doable since the us cars prior to 2009 came with them. Perhaps mb will change it out if i complain enough since all the us brochure and manual clearly states you can control rear temp from front. False advertising?

fs1013

My SA passed along the question to MBUSA Customer Services and they called me to clarify the issue. He took the time playing with a GL (MY11) and confirmed it did exactly the same as ours. So he contacted MB Germany and called back again confirming we haven't done anything wrong. The manual provides false information on this one and I can't adjust the rear temperature from the front control panel for the US model, only to turn it on/off. Although a little disappointing, still have to give them a thumb up for taking the time to response.

Just looked at MBUSA website, the introduction of 3 zone automatic climate control option still advertising: "The rear-cabin settings can be adjusted from both the in-dash and 2nd-row control panels".

Looked at the MB Canada website too, their system even has a name: THERMOTRONIC and looks much better with a digital message display, and cost pretty much the same for the option. Not sure why they have to make it differently, for Celsius and Fahrenheit?

Brocktoon

So you are telling me that in the US you get a true three zone THERMATIC? I thought they were all THERMOTRONIC, like everywhere else. Just to be clear, do you have a knob on the back of the centre console, and vents in the roof?

dougpark714

This is disappointing. Prior to 2009, the US models came with the digital system -- you can change the rear temp on the older control. Not sure why they changed it for US. I wonder if the control can be changed to the older one or the one offered in Canada? Could be an easy upgrade. The climate control panel comes off very easily.

fs1013

Yes I do have a knob on the back and vents in the roof. The difference I can see with mine compare to the Canada version (and rest of the world) is that the front control panel doesn't have a message display and the buttons are layout slightly different. You can see it on the MBUSA website here: http://www.mbusa.com/mercedes/vehicl...350BTC#options Find "3 zone automatic climate control" and click the picture to enlarge.

I'm not familiar with the terms THEROTRONIC and THERMATIC. I do not see them in my owner's manual, brochures or MBUSA website. So I don't really know the difference.


It is disappointing indeed but I think it's not worth considering an upgrade. I am surprised though that they are still claiming you can adjust the setting from both the dash and 2nd row control panels on their website. Well, they can say the setting means on/off I guess.

Brocktoon

Wow! that is weird! That is Thermatic. I have that as the base option in Canada. All three zone GLs I have been in/seen elsewhere (London, Zurich, Prague, Russia, Ukraine) have Thermotronic, just like Canada. Thermatic is pretty basic, Thermotronic is computerized and looks at extra parameters like brightness, albedo, humidity etc and is a true three or four zone. No wonder you guys are having problems...

fs1013

Thanks Brocktoon. This is what I got back from my SA and thought I should share:

"Your car does have the climate control dust filtering system and sunlight sensors as well as humidity control, so you do have these features on your car.... so I assume their Thermotronic features, except the rear control, are the same as our premium climate control system....I don’t know why the feature to adjust the rear AC from the front control was not made available to the US market; it might have been part of an option package that interfered with some other design requirements for US import – this is purely speculation on my part."

Anyone knows how to verify whether those filters, sensors and humidity control exist in the car?

As for the rear zone temperature preset, this is what I was told:

"The rear climate control is hard wired to reset to 72 degrees which was deemed to be the neutral comfort setting. This way the rear does not pump out AC at inappropriate times if it is left on inadvertently by the last user."