This is exactly what the ice cube does!
low pressure switch remains active.
What did you do differently than the ice cube?

Pull the Klima.

Test the resistance of the compressor speed sensor using sockets 9 and 11. The value needs to be between 530 and 650 ohms or the sensor needs to be replaced.



Check the voltage for the RPM signal using sockets 1 and 2. Nominal value for ac volts is greater than 2.8V. Engine must be running at idle.

The Kilma on the SDL in my opinion is unduly complicated. It monitors too many inputs. The RPM sensor uses an electronic comparator to monitor the engine and compressor speed and cuts it off if there is a discrepancy, but how big is the tolerance? It is impossible to fix the circuit or increase the tolerance unless you have the schematic of the relay. I replaced the IC once and no luck. As a result, I just hack the circuit using ANY gas Kilma. I bypassed everything with the exception of Pin 10. Pin 10 is controlled by the CCU so the A/C button and low pressure freon sensor are in play and nothing else. Pin 10 is active low. The downside of hacking is that if the compressor got stuck then it may shred the belt. I have been using a hacked Kilma for 2 years and so far so good. It is a chance I don't mind to take.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

will smoke.

How often does that happen? I've never, ever heard of it happening on the VW forums...

Thanks Brian,
Will do.

I cleaned the compressor clutch today with carb cleaner and pieces of card board. It was really dirty in there...took me half a can of cleaner and I believe it was worth while. There was a lot of dirt and oil in there.
After this the compressor was engaging and KEPT it that way. I'll do further tests tomorrow.
If it is true that it was a dirty clutch...then I am just happy.

That's good work, Martin.

If the clutch slips just the slightest bit............the Klima dumps the compressor and must be reset with the ignition switch.

I'm hoping that the renewed clutch was your issue..........a cheap fix!

Thanks Brian,

This was luck. Sometime I am lucky and then most of the time I am not.
Still trying to get the temperatures down. I can't get below 55 F at the vent...too bad.

I'd still like to see what happens if you jump the ETS and let the compressor run steadily.