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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53148
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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Thanks again in diagnosing a bad S.A.M. Now

Customer Question

Hi thanks again for guidance in diagnosing a bad S.A.M. Now I need help in getting the A/C working. By the way this car did have front end damage, and it looks like they only did cosmetic body work to sell the car. ..First, there was no pressure in the
system. I added freon with florescent die. The system is currently holding pressure but compressor is not turning on. Blower and condensed fans are turning on. This is only what I have done. By the way this is the two door hatchback model.
Submitted: 1 year ago.
Category: Mercedes
Expert:  Marty replied 1 year ago.
Hi, was the a/c giving problems before you replaced the SAM?
Customer: replied 1 year ago.
I bought the car with the a/c not working
Expert:  Marty replied 1 year ago.
Ok, power to the compressor comes out of the left front SAM. Any chance you can get the vehicle scanned for fault codes? If there are fault codes stored in the climate control module they can keep the compressor from engaging. If you put power to the compressor does it blow cold air?
Customer: replied 1 year ago.
I have not attempted to put power to the compressor,and don't know were to at the front left S.A.M! I have a OBD2 plugged in and all codes are power train related .P0172.P0600.P0130.P2014.P201C.P2046.P202C.P2029.
Expert:  Marty replied 1 year ago.
The fault codes will be stored in the climate control module. You really should get the codes checked. You can put power to the compressor right at the blue/green wire at the top of the SAM at connector 21. Copy and paste the link below for the connector location.
http://www.mediafire.com/view/a86p3nxie17hdw2/Capture.PNG
Customer: replied 1 year ago.
It seems that you are saying there is a different place to get codes for the clima te control module, other than the obd2 plug under the drivers side dashboard. were is the connection at to plug in the scanner and the name of the tool that reads the codes. I might just buy it.
Expert:  Marty replied 1 year ago.
You scan the climate control from the same connector but you need a scan tool capable of reading all of the modules in the car. There are some Mercedes scan tools on ebay but I don't know anything about the people selling them or how well they will work.
http://www.ebay.com/itm/Mercedes-CLC-203-Diagnostic-Scan-Tool-Reset-Code-Reader-iCarsoft-i980-/291241523189?pt=LH_DefaultDomain_3&hash=item43cf58f7f5
Customer: replied 1 year ago.
Hi at front left Sam M18 terminal blue has 12 volt and blue/green doesn't. I disconnected the plug and checked for resistance. Open circuit. Also I turned of fan and ac control in car, but still show voltage at blue wire and ground at blue/green .M18 terminal
Expert:  Marty replied 1 year ago.
If you put power to the blue/green with a fused jumper will the compressor operate?
Customer: replied 1 year ago.
I used multi meter in line set to 10 amp setting and it drew 1.06 amp when putting power to blue/green, but compressor did not engage/turn on.
Expert:  Marty replied 1 year ago.
How did you connect the meter? Did you go from the blue to the blue/green?
Customer: replied 1 year ago.
Yes when checking for volt, but when trying to put power to the blue/green i put the other lead to a fuse that had power. And showed 1.06amp draw when connected
Expert:  Marty replied 1 year ago.
Ok, at this point you need to get connected to a Mercedes scan tool so you can get the codes from the climate control module and the left SAM. It may just be a matter of erasing the fault codes in the system to activate the compressor or there may be a fault code for one of the sensors that is keeping the compressor from being activated.