I input 12 V into the poles of an '82 380SL's Idle Speed Adjusterand heard a clicking noise, once. Is this a proper response from a properly functioning ISA or should it be whirring or what?

I read that the proper operating voltages of the ISA are around 4-5V but I've put in a new ICU so assume I'm getting the correct input voltages for the ISA, and the new ICU did notimprove onthe incessant idle surging, so am trying to come up with a way of testing the ISA without replacing it.

If no, how should this be done and what exactly are the results for a properly functioning ISA, please ?

Also, if I find that the test reveals malfunctioning, can it be repaired and if yes, how ?

Thank you,

Courtney

 

Run the car at idle, disconnect the idle speed adjuster while running, idle should jump to 1500 rpm. Try that first. Is it surging, high idle, rough idle?