2008 sl550 r230 A/C not cold and blowing hot air
 

My A/C is blowing hot air not cold? any advise

thank u

It could be many things. First of all, set the temperature controls to their coldest setting. See if it changes based on top open vs. closed. If you set the temperature dials to the warmest setting to verify that you get heat. If none of that helps, then my question is, "Are you going to DIY this repair?" If not, take it to a mechanic. If you are going to DIY, the next step is to put gauges on it and read the pressures.

I would check high and low side pressures as Rodney suggested. If you haven't got a set of gauges, then consider investing in a diagnostic tool. Among useful statuses Star Diagnosis can display the high side pressure and the control signal the in-dash climate controller is sending to the A/C compressor.

I would check high and low side pressures as Rodney suggested. If you haven't got a set of gauges, then consider investing in a diagnostic tool. Among useful statuses Star Diagnosis can display the high side pressure and the control signal the in-dash climate controller is sending to the A/C compressor. The cheaper iCarsoft tools probably can as well.

My Mini Cooper would do this almost annually as the clutch on the compressor would go bad. That was the one issue I had with the car. I think since 2009 I went through 4 compressors.

They say a picture is worth a thousand words:
https://cimg2.ibsrv.net/gimg/www.mbw...bc8504ff4e.jpg

I know a lot of people bad-mouth those recharge kits, but if you know what you are doing with them, they are fine. I will say that the gauges on them tend to be of fairly low quality.

Yep. Also worth noting for the OP, Is your AC Off button illuminated? When you press it, does the red light extinguish and then relight itself a few seconds later? That's an almost sure sign that you need refrigerant. If the system is just low, then recharging is as simple as adding refrigerant via the port on the left side of the engine bay near the ABC Resevoir. . Just remove the black cap and attach the hose to the port. The can will become very cold to the touch when it's filling That's how you know the refrigerant is indeed flowing. But if it's too low or out, then the climate control computer has to be reset which can be accomplished either with STAR or ICarsoft MBII (I'm uncertain if the iCarsoft i980 can reset the climate control. I know it can read the fault, but don't know if it can cycle & reset it? The MBII & Star definitely can do both)