96 e300d a/c problem
 

Hi Guys
My a/c compressor wont come on and the ec button light wont turn
off. I ran a 12v hot wire to the compressor it turns on the car get cold but
the light stays on. The system needed 2 cans of 134a. Whats my next
step? Thanks Greg

There are diagnostics that you can run with the climate control pushbuttons. Use the search function to find them on this forum.

Almost certainly your pushbutton unit has a stored code for low refrigerant, which will cause the EC lamp to stay on and the compressor to stay off. Now you will probably also have a code for a bad electromagnetic clutch due to disconnecting the wire, so you can ignore that code when you read them.

Did you ensure that you had positive pressure in the system before adding refrigerant? If so, you should have it sniffed for leaks. If not, or there was no pressure, the dryer should be replaced also.

96 e300d a/c problem
 

Hi Guys

Thanks for the reply. How do you clear the error codes on the control
unit? If the belt slips will this cause the compressor not to come on ?
Could the ec button be bad causing to stay on ?
Thanks Greg

Unlike older cars, there is no compressor speed signal. Thus, a belt slip will not directly disable the compressor, for example when the belt gets wet. However, if the compressor locks up, the belt will slip very badly and will blow the (non-replaceable) thermal fuse in the clutch.

Search for the procedure to extract the codes. The last step is to clear them. If you didn't clear any codes yet, don't suspect anything else until you do. Be sure to write them down.