1995 E320 Check Engine Light

I'm having a problem with the check engine light.
The light will come on when the weather (SF Bay Area) (warm and dry except during the winter) changes to colder and more humid. The light
was on and while the car was in Nevada, i.e., dry environment, for a weekend the light turned off by itself. If the light is turned off by a service tech, the time delay before it comes back is directly related to the environment - the colder and more humid the sooner it will come back on.
MB has looked at it several times. The codes doen't seem to be consistent.
One time the codes were: 004, 019, 035, 084. Another time the service tech wrote:"found trouble codes for fuel injectors, air injection pump, collant temp sensor, and o2 sensor. Only symptom is air injection pump is running at all times. Installed new sensor but problem continues. Suspect engine control module is faulty - suggest replacement. Estimate = $1860."
My intution says moisture is getting somewhere that it shouldn't. Before I allow the stealer to throw parts at the problem, I wonder what you all think.
Other interesting problems are the mind-of-its-own radio antenna, and the cruise control. I'll cover those in separate posts.
Thanks!
Rod
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i would get a can of contact cleaner and unplug every connecter clean it good with the cleaner and scrape ALL <if any >green or any thing else growing on or in the plugs.
i would do 1 at a time and mark them as you go.
make sure the ones that have a clip that hold them together you don't break the clips
the case, minus a few cans!
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There was a recent post from an owner of a '95 S320 whose engine wiring harness's insulation was faulty and the harness needed to be replaced.
As a precursor of the eventually larger problem humidity may be triggering sufficient current leakage to trip the Check Engine Light and give conflicting codes each time. It will only worsen with time.
This isn't an unknown problem with M-Bs of this and earlier years.
If you find the harness does, in fact, need to be replaced you can DIY and save a lot of labor cost. One sketches how the wires run and connect and then lay the new harness over the old one and slowly and very methodically remove the old and connect the new. That's the only way it can be done - by anyone, you or a $100/hr mechanic.
If I owned this car I'd live with it as long as possible and replace the harness later rather than sooner, but know that reliability will be compromised.
Another thought: This engine has three coils or spark plug wire connectors ($15 each). These fail over time and affect the ignition. Were the ones on your engine ever replaced? Easy DIY job.
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