1992 500SL A/C problem

[lplb]

I have a 1992 500SL and the A/C compressor keeps running constantly.

Neither the "0" ((off)) nor the "EC" on the climate control unit would stop the compressor running.

I bought a new climate control unit and it still does exactly the same thing: the A/C compressor keeps running even with "0" or "EC".

Could someone kindly tell me what I can do to resolve this problem please.

Thanks.

[Philip Justice]

lPlB, Phil Here. I had the same problem with my Sweet 92 SL, For me it was a stupid simple thing. On my Dash I have a " Roller " temperature switch, If I roll it down beyond the " Blue Limit" and feel a "Click" your compressor will not come on. You can then run your system on Economy.
I think this is the way the car was built. It worked for me.

1992 Sweet 500SL Phil Justice

[lplb]

thank you for your kind reply. i dont think this is it because turning the temperature selector to "LO" (( after the click )), according to the owner's manual page 23, means heater turned off. Also, in the past winters, i can always use "EC" at about 66F, and according to the manual page 25, "EC" means the compressor will not engage.

I have learnt from the Benzworld website that more than likely i need to replace my Engine Systems Control module, because it is supplying constant power to the compressor independently of the climate control unit on the dash. Anyhow, hopefully it would resolve the problem.

By the way, have you come across any posts that talk about replacing the 9004 halogen headlights with 9004 high and Low HID ? Please kindly let me know about it if you have.

Have a good evening, and thanks again.



lPlB, Phil Here. I had the same problem with my Sweet 92 SL, For me it was a stupid simple thing. On my Dash I have a " Roller " temperature switch, If I roll it down beyond the " Blue Limit" and feel a "Click" your compressor will not come on. You can then run your system on Economy.
I think this is the way the car was built. It worked for me.

1992 Sweet 500SL Phil Justice[/quote]