Odd ACC problem
 

The A/C compressor on my '87 300D turbo seems to be on all the time, even when the ACC is set to Econ. The only time it isn't cycling is when the whole system is shut off (button furthest to the right is depressed.) The compressor itself cycles on and off properly so it doesn't appear to be a short to the compressor clutch. Everything else works perfectly; heat, cold, maintains set temp., etc. This isn't a big deal except that I seldom need A/C here this time of year and it's kind of a waste to have it on all the time. I'm not sure where to start with this problem.

Could it be the push button unit in the dash?
or maybe the freon switch on the receiver that switches the compressor off when the freon level is low.

Are you sure the compressor still engages when it's in EC?
Have you looked at the compressor itself?

Good luck,

I think its ACC unit Econ button. There is some mess up in there behind that button.( Unless someone had opened it in past and wired it wrong) Also check if AC comp is off if you push the Normal button( the one next to economy). Its definitely some mess up in wiring. I am not so sure about the low freon switch. though I would check the condition of connections on it.


Let us know how it goes.

MVK

Sorry one more thing. Try gently tapping each button esp the econ and normal button a few times.

MVK

The compressor is definitely working properly. It cycles on and off as it should and I can feel it cool. I checked everything again and noticed that on the defrost setting I can get the fan to go on and off if I wiggle the button a bit. I think I have a wiring problem behind the panel. I'll check it out this weekend and let you know what happens. Thanks for the ideas.