Mercedes Benz repair: My mercedes 1987 300e AC does not work., climate control unit, speed sensor

Question
The ac on my 87 300e does not work. First I took it to an expert and he said the part that is mounted to the fire wall was leaking so I changed it. I cant rememer the name of the part sorry. Then I charged it with r12 3 cans. Nothing happend. I took it in again and he said that the compressor was bad also. Went ahead and changed it also. Replaced the Dryer and the belt and the water pump all at the same time. I have the same problem charged the system with 3 cans of r12. the r12 is in the system now because is visible on the little window of the dryer, but the compressor only engages sometimes, or maybe 1 time and then it stops. I looked at anothere 300e and the compressor soped running also but the air was coming out cold. I read the question with the previous 87 300e, but maybe you might of got new information about the problem.

Thank You Very Much

Answer
Suggest you join this forum, and search A/C issues.
Technical Information and Support
http://www.mercedesshop.com/shopforum/forumdisplay.php3?f=1

The problem you describe is not the R-12 system charge or compressor.
Logic says your A/C issue is electrical:
A bad A/C ground wire...
A/C ACC Temp Sensor...
A/C E.T.R. Switch...
A/C Pressure Switch...
A/C Relay...
A/C Speed Sensor...
A/C Temp. Switch...
Climate Control Unit...
Sampler Blower Motor...