W202 C43 AMG HEVAC playing up

Discussion in 'Electronics' started by DRBC43AMG, Jun 19, 2019.

  1. DRBC43AMG

    DRBC43AMG Hardcore MB Enthusiast

    Messages:
    1,079
    Joined:
    Mar 15, 2010
    Location:
    Switzerland, Sion (VS), the canton of mountains, w
    Car:
    99' C43 AMG "T Rex", 00' Renault Twingo1, Ultima Sports Can-Am
    Don't know if this is the right place, but I have a feeling that the problem and question are electric related, hopefully...

    The weather and temperatures is finally looking like real summer and with the rise of the heat, I had my A/C checked and refilled. It had lost some gas since last year at the same time of the year approximately. I think that the compressor is getting on in age (20 years) and it looks like OE factory fitted.u When sing an UV light, I can see some traces of the fluorescent dye around the unit. So I guess there must be a small leak, but not enough to stop proper operation.

    Previously when the cabin was hot after a spell in the sun, when I switched the engine on, settings of the HEVAC on Auto, the fan would kick in and work up to full speed in a couple of seconds. The LED control screen on the HEVAC control unit shows clearly the max speed reading. Then a short time later after 10 secs approx, the vents would shoot out a blast of cold air over and above the fan's full speed, like if a second fan kicked in. This way the cabin could cool quickly and a short time later the fan would gradually reduce speed so that the occupant(s) didn't freeze!

    Already last year this extra cold blast didn't work regularly. You could clearly hear it cutting in and out, but now it no longer does it.

    Any ideas what could be the problem? Could it be the fan's regulator as I assume the fan has one?

    I may scan and see if any codes show up
     

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