sound 8

For God sake can anyone tell me when the light is on, is my air con on.
Or when it's off does that mean it's off. This is the red light on my air con
button. Yesterday I got cool air with it both on and off.
Any help would be grateful, or are you as confused as me

aluthman

Light on = AC on

Karl G

It's probably different in the UK, but here in the USA there are two variants of the climate control. On the lower-power cars (mostly non-AMG) the button says "AC" and the air conditioning is on when the LED is lit. On the higher-power cars (mostly AMG) the button says "AC OFF" and the air conditioning is on when the LED is NOT lit.

BeltFedBob

On my SL the light indicates the AC is off.

aluthman

On my SL55 and an SL65 I saw the other day, the button is labeled "A/C" and not "A/C Off"

Quadrobenz

On my SL600 2005 and S65 2006 light on is AC off. On my 2007 E63 light on is AC on.

GFEAR

GREAT, I WASNT CONFUSED BEFORE BUT NOW I AM

OUTCAST

Man what was MB thinking about with this AC switch. Standardization comes to mind (Oops I said it )!

Sathinas

Because reading the owner's manual for a particular car is just so hard...

FLSL55

Guys!

It seems that the A/C is on ALL the time if the blower motor is on. My car blows cool air with the A/C light ON OR OFF. The only way for me to turn the compressor off is to turn the whole system off.

I can't find a way to get ambient air through the vents without the A/C being on.

GFEAR

YO LIVE WHERE I DO, I NEVER SHUT IT OFF, ITS TOO DAMN HOT.

I CANT STAND HOW YOU CANT RUN THE AC ON HIGH WITH THE TOP DOWN, I NEED TO FIND A WAY TO TRICK THE CAR SO IT THINKS THE TOP IS ALWAYS UP

FLSL55

As a side note

When the A/C is on the IAT's skyrocket. If you want lot's of power, turn your A/C off.

My IAT's are 30 degree's hotter when the A/C is on.

sound 8

Yes! in the UK you really don't need a/c on much of the time, so I would
like to turn it off, gives me a bit extra power as well. I think MB handbooks
are the most difficult to understand! But as I said with light on or off
I can still feel refrigerated air.
Thanks guys anyway!

GFEAR

MOST CARS THE AC TURNS OFF AT FULL THROTTLE ANYWAY

Quadrobenz

That is strange. On my cars the compressor appears to be controlled by the AC switch. The system does not deliver chilled or dehumidified air with the AC Off switch activated.

mdotpoker

So to add even more confusion, what do the red and blue buttons on the dash do if the button below turns the AC off and on?

Late

I think you are feeling the air from the chilled center console compartment ... The air conditioning unit remains on at all times to keep that center console cool for your cigars, flat sandwhich's, gum, condom's, Etc... The cold air that you are feeling is just residual air from that. No air should leave the vent when the 0 button has a red led showing and when the ac off button is on the air that is coming from the vents is from the fans. If you are in the UK rub your left leg up against the center console next time you go for a drive and you will see what i am talking about.

Hope this helps

sound 8

Interesting, makes sense if it does.

Well guys it seems we all have problems with this, I don't have a refrigerated
center console, i did on my SL55 but yesterday it was an normal day, set
my temp at 20 and drove with the a/c rest button lit up, certainly chilled air
was coming from the vents, then I turned the a/c rest button off, no light.
Waited 10 minutes driving around 70 and still chilled air came out.
HELP!

FLSL55

BUT, your Intake Temps (IAT's) will already be over 130F if the A/C is on. So when you punch it, you'll already be down on power and the temps will rapidly rise from there. 99% of the SL55 guys/gals don't give a crap though.

The A/C has to be turned off for at least a couple minutes for the Intake Temps (IAT's) to drop enough for the ECU to give full power and not pull timing when you get on it.

Off topic...sorry

sound 8

How can intake temp be 130f, I presume you mean air drawn in.
Then you say .. so when you punch it in... punch in what, the a/c button so
it's on or off the light I mean? That's the whole point.
In my SL55 I could turn it off easily, and always did when racing.
You say it has to be off for at least 2 minutes, trouble is I don't know when it is, off I mean.

Sathinas

Are you sure the A/C clutch isn't stuck to the pulley, either by foreign material being wedged in between the clutch assembly an the pulley?

Disconnect the A/C clutch plug and put a meter on it. Turn the A/C off in the car. If you're not getting voltage, then it's your compressor or clutch. If you're still getting voltage, then you have some other issue(s).

You may have to have the engine running to do this test, don't know it the HVAC unit will power the A/C clutch with the engine off (and key in RUN).

FLSL55

Sound,

I own a Scanguage II. It shows me my boost in PSI, My Intake Temps (after the intercooler), Timing, Oil temps, coolant temps et et et

Our cars have an air to water intercooler. It takes a few minutes to cool down the intake charge when you have run the car hard or you have been idling in traffic OR running you’re A/C system.

Just turning off the A/C in our Supercharged 55k engines doesn't work the same as a naturally aspirated car.

What I mean by "punch it" is go to full throttle.

sound 8

I realize that the 55 is totally different being supercharged, but will full
throttle on my nat *** 63 turn the a/c off. It's a bit drastic having to drive everywhere at full chat though, there must be another way, but thanks
anyway.

sfovc2003

O.k., pull the a/c system if I want to go faster (like, just what I need).
But I'm still not sure what the answer was to the original question:
On a U.S. SL55 that has an A/C/ button labeled "A/C" and with the word "Off" in smaller letters off to the left, is the A/C on or off when the red light is on. On or off only please.

GroovyMambo

if your button says AC OFF, when the red light on the button is on (glowing red) the AC is OFF, thats how it works in my car - 2003 SL55 USA