Quote:
Originally Posted by kuene
ETS is what I've seen some people/docs refer to the "evaporator temp sensor" as.
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Do we know if this is electronic or mechanical?
Other older brands are mechanical using a sealed system consisting of a sensing bulb / capillary tube / thermostat to sense evap temp. Basically, this is a remote sensing device where the sensing bulb and tube are filled with gas that expands when hot and contracts when cold. This gas presses on a diaphragm that then actuates a switch. If this gas escapes, the switch will think things are hot and let the compressor run.
There are also situations where worn contacts will weld themselves together causing the switch to stick on.
If you have such a system, is it possible to bring the sensing bulb out and stick it in an ice bath for testing?
Quote:
Originally Posted by kuene
I'll get accurate pressures using the method you and others described. I don't have the mercedes CC manual, but in the Haynes AC book, there is a table of pressures and for 82 mercedes diesel I think the high pressure was supposed to be around 230-250 or so. No idea if those tables in that book are to be trusted.
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A pressure chart for R12 won't work with a R132 system so using pressure ratios will be needed.
Quote:
Originally Posted by kuene
for the r134 charge I put in exactly 80% of the r12 weight specified on my radiator support tag - I read up on the ranges from 75-90% and did not want to over charge initially.
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Lets see what the actual pressures show.
Quote:
Originally Posted by kuene
If the condenser drain is that foam tube that goes down into the transmission tunnel - I replace that disintegrated engineering marvel (foam???) a while ago with a piece of rubber from a garbage disposal drain kit. I have what looks like normal condensation draining out from under the car when the AC is in use.
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Yep some sort of drain tube. Given you have water coming out, it should be OK.
Another thought, I've pulled a few evaporators on various cars that had leaves and other debris clogging the fins, this would lead to reduced air flow and icing.
Is there any way to look inside the AC box?
Quote:
Originally Posted by kuene
the electrical wiring/relays and such related to the fan and compressor appear to be functioning correctly. temp and pressure switches on receiver are new (as is receiver). If one of those switches were faulty, would they default to OFF or on? Compressor is working so should I assume that switch is getting enough pressure to complete the circuit?
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My concern is that something was jumpered in the the past allowing the compressor not to cycle when low side pressure drops too low / evap temp is too low. A factory manual would offer principles of operation, from there we can figure out what it going on.