W124 A/C Wouldn't restart until car was restarted. - Page 2 - PeachParts Mercedes-Benz Forum

shertex · #16 08-09-2013, 01:24 PM

When I had same symptoms on 92 it was a bad Klima....actually found one used for $25.

jay_bob · #17 08-09-2013, 02:08 PM

Quote:

Originally Posted by jcyuhn

You tripped the rotation sensor circuit in the Klima relay, so it shut down the compressor until restart. Don't over-rotate on this; start with the simple stuff. Two common causes of this scenario are excessive air gap in the compressor clutch and dirt/oil on the friction surfaces. The air gap is specified as 0.50mm. In my experience compressor engagement becomes unreliable once it increases to 0.75mm or so. If the gap is too large you can reshim it to adjust downward. A good automotive a/c shop will sell a kit of shims for the Denso compressor.

Degreasing is as simple as using a good spray of simple green, or brake parts cleaner, or whatever works for you in the clutch air gap. Rinse with water and see if it works better. Sometimes this is enough to get solid engagement and not trip the rotation circuit.

That was the direction I was heading, since Kris is a EE, I took a chance he might have access to a scope, and be able to see if the waveform coming from the sensors was erratic. Trying to rule out sensor or Klima problem from up top since the compressor is kind of difficult to get at.

These sensors do have a high sensitivity to contamination and misalignment, that is good advice if it turns out to be a weak signal from the compressor sensor.

Bob338 · #18 08-09-2013, 02:42 PM

That's a classic symptom of the Klima.

It's likely with your talents you can do the same repair as on the cruise amplifiers. The Klima for mine runs $140.

I had the same problem and didn't try to re-solder the old one.