[W126 Coupe] Automatic Climate control.

[Jay Hirsch]

The only thing I have found  the climate control units of MB's prior to the 1990s  are basically the same as the first climate control units used by Cadillac in 1964 and used through the late 1960s.

By 1970 Caddy  had the  units down, and they are bullet proof since.    Was riding all day yesterday with the a/c on in my 1976 Eldorado.  Last week had my 60 Caddy   out with the a/c on
Both cars have never had the a/c unit touched.  Just an  occasional adding of freon which I get from a supplier in Canada.

Seems Mercedes had engineers who know mechanics on cars.  Suspension, handling and to some degree  motors, especially diesels.
But knew  beans about electronics and creature comfort items such as power windows,  a/c, etc. when they first appeared on MBs in the  late 1970s  and the 1980s

Harrison cooling was a division of  GM


Mercedes chose the right compressors to use but the wrong  climate control units.  Should have used GM  units from the late 1970.  But MB did not want pay.

My 1987 300 SDL has had some "annoyances" with the a/c... heat.  I have several climate control units on  shelf  and the few times  the past eight years there was a problem  I pop another  unit in.

Now a leak in the system is something else.  The compressors are York which are bullet proof unless the clutch goes which means a new compressor

My advice try and get some used climate units  for under $60  if you can.  It is a fifteen  minute job  to change  units and the simplest way to see what "problem"  exist is if any.

just my two cents. but been there and have "done that several time"
keep cruisn
Jay H

You can always use the tried and true   4/60   a/c  unit.        60 mph with all four windows down, never a problem


On Aug 22, 2011, at 2:55 PM, Carl Hansen wrote:


> Last time I drove my SEC in the hot weather I noticed that the a/c stopped working after a while. I did see the message that a couple of other members had the same problem so I figured I was in the clear.

> I checked the Aux. fan bridging the gap as described and it works. I pulled both relays one which is for high and the other for low speed Aux. fan.

> Both relays are working as I placed them alternately in the high speed fan socket but it seems that the low speed doesn't work. Is this because it is temp sensitive, I am guessing that the fan comes on slow at first then faster when required as the temperature reaches its peak? I let the engine run with the car half way out of the garage and a/c on full blast. Engine reaches full operating temp,a/c is cool at first, then goes on to blow warm 70f air and aux. fan never comes on.

> Finally I thought perhaps it could be the temp. sending unit on top of the thermostat housing. I connected the two prongs to my ohm meter while engine is hot of course, full contact. I replaced the plug, no fan, bridged the wires, fan comes on full blast. While I'm standing there wondering why the fan runs when I bridge the wires but not when I plug it in to the closed contact, suddenly the fan started up all by itself with the wire unplugged. Maybe I should go out and look for a pinched wire somewhere. That proved negative, no pinched wire. I checked it again this time with everything shut down. Turned ignition on pulled the sending unit plug and the fan came on, I'm baffled, any ideas out there.

>  

> Carl H

> 1988 560SEC

>  

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