My a/c clutch is not engaging, and the EC light is lit always, except when I put the controls into Defrost, but, the a/c clutch still does not engage.

I found this thread C230 A/C Diagnostic display (Climate control)--How to use

I pulled the codes. Now bear in mind, I have lost some pixels on the pax side, so my numbers may be wrong. I pulled 416, 231, 235, and 234.

Just before I noticed I had no a/c, I did seize the belt tensioner pulley, melted the belt at the pulley right after a cold start in the winter, the car backfired, the engine quit, I was able to start it right back up, quit again without backfiring, and then I was able to restart it and drive a couple of blocks to get off the road.

I am guessing that's why I have codes 416 and 235, because the belt seized. I do not know what an ECT(231) sensor is nor a Sun sensor(234). As a side note, I occasionally set an EGR code, but the valve has been replaced. I do not know if this plays into the CCU. I did clear a set code before pulling these CCU codes.

How do I clear the codes and start over? I can't seem to find out how to clear them here.

I did hook up a gage on just the low side and I do have refrigerant pressure.

I also have a Snap-On Mt2500G, but no S-33 key, which is the one for the ac system. I just ordered an S-33 and a S-34 key so I have all the keys for my car. Will the scanner clear the codes so I can start over once I get the personality key?

Any help would be appreciated.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport