AC Control not working - EC mode always on
 

Hi,

the AC Control unit on my 1996 E320 is not working anymore. The EC button for economy mode is always on resulting in no cooling. It is not stuck but no matter pressing on it how many times the lamp is always on. All other buttons are fine.

How can it be fixed?

Thanks!

Most likely is low refrigerant charge (due to a leak?). Second most likely is a pressure/temp sensor. No A/C since compressor isn't running.

I would have an A/C tech do an overnight vacuum test for a leak. No point in recharging until you find the leak as the hole in the ozone layer is already big enough. :eek:

Thanks Richard,

I asked my friend who has a 1998 e320 to stop by. We exchanged the AC controls for the test and the failure is apparently with my unit, meaning it has also same behavior on his car and his unit works fine on my car. :confused:

Problem is fixed after running diagnostics and erasing all faults! EC button is functioning again, although fault B1422 is recurring, but it's another story.

The refrigerant pressure readout is 13 so it should be OK, I guess.

Thanks a lot!

Glad to see you got it worked out. In case you don't have the definition list B1422 refers to a issue with an electrical connection to the instrument cluster.