85 500 sec wont idle
 

anyone out there got some info why i cant get this car to idle, i am kinda leaning towards the idle control valve, i took it off and i applied 12 volts to it and there is clicking coming from it, when i reinstalled it i noticed that i have no voltage coming to it, at this point im lost, any direction would be appreciated . thanks

I had same prob
take off air cleaner
start looking at the small vaccume lines-cracks-not attached etc. the vaccume seems to be the trick- I taped alot of the connections and just basically touched each one and it fixed mine.I thought there was something major wrong. now it runs better than my S500

Sounds like the Idle control module to me. rap on that sucker with a screwdriver handle smartly to see if it dies. if the car dies then the solder connectons in the ICM are bad(cold joints). replace it. I had troubles like your on my 380SE and I found that if I rapped on the ICM the car would die. Did it twice to make sure it was me doing it. then replaced the ICM. Fixed it and no more wandering of idle also.

You might also look to make sure that the throttle position switch is plugged in, and functioning.

On my car, when I forgot about it after an engine swap, the car would idle around 1100 rpm. Once it was reconnected, or even just jumpered on the fender side of the connection, the idle dropped down to 600 rpm.

The idle control solenoid in front of the air cleaner could be the problem.

It is not uncommon on the Mercedes Benz W126 SEC coupes to have a problem there