Low side cut-out; an 'absense of refrigerant sensor' if you will. Like I said, I'm not an MB tech, but I would assume the A/C system would be equipped with one. I know my '85 grey market 380SEL has one.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

There is no low-side cut-out switch. M-B's have a low pressure cut-out switch on the high-side line (as do all other TXV systems).

I hope you're referring to "all other TXV systems" in MB's ONLY. Most other manufacturers have their low pressure switch in the low pressure line, becuase it makes more sense to do so. A high side pressure of 30 psi in the high side is a VERY low pressure, and likely to not be circulating compressor oil.

I'll be the first to admit, I know little about MB's, but I've spent 15 years wrenching on every other make, along with handling stationary, residential, commercial & "other" systems.

You could absolutely be correct - but having a low pressure switch on the high side seems silly, especially since a leak on the suction side could easily not trip a low-side switch placed on the high side because the compressor could still pump atmospheric air above 30 psi.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Hi,
The Low side was 55 and the high side was 250.

The Fan came on and the Low side stayed 55 and the High side went to 225.

Do you know if you have a compressor speed sensor? If you don't, the easiest way to find out is to find the cable going to the compressor. One wire means no, three wires means yes.

If you do, look for anything that may cause slipping. Oil on the belt or clutch would do it, and a worn clutch might. Water on the belt too, but that would only occur when it rains.

There is an Electromagnetic RPM speed sensor on the compressor. The belt was just put on yesterday?? But you guys are sure trying to latch onto belt slippage. Is there a possibility the sensor is bad? Also the clutch engages 100% on a restart.

I know that I am correct. Most other manufacturers use CCOT systems, and these do use a low-side cut-out switch. However, most (but not all) European cars use TXV systems which do not cycle during normal operation. The only thing that cycles a TXV system is the evaporator temperature sensor.