I was driving to town yesterday evening and turned the AC on. after about 30 seconds i became worried because the air was warm and it was pretty cool outside. i told my wife that i thought my AC was not working but she said it was. Her two vents were nice and chilly but mine had the heater on!?!?!? how does that work?

on the drive back it did not do it, but i still want to know what i need to check out. any suggestions?

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Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Not possible. Take a look at the ducting for the vents and you will see what I mean.

I had to check your profile to ensure that you didn't have a W210 E300. You don't, but you have something very strange sitting on your desk. What is it?

It appears to be a plexi glass AMD logo, with water in it. Perhaps the cooling unit for his "ArcticAthlon"? There's something in it....can't tell what it is...a pump? peltier...?

AMD logo:

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

lol., ya it is a custom watercooler that i built. it has a showerhead in it, where a fan blows cold air right past the droplets. the heat exchange is ridiculously high, and it works so well that we had 3 computers hooked up to it at once. i was using a 220Watt peltier, my friend had a 125 watt peltier, plus the heat of about 3x100 watts for the overclocked processors. The processor temp was only 15*C, and i had my $75 AMD processor overclocked from 1.466Ghz to 2.85Ghz, which was faster than it was possible to buy (and yes i am still using it, 3 years later, so i did not kill it by overclocking).

I displayed this at MilllionManLan(1,057 people gaming for 5 straight days) in Louisville, where i won 2nd place in the case modding contest. they did not give me 1st place because people complained that it was not part of my case, only external. it was still the best thing at that lan party and AMD (was a sponsor there) gave me tons of computer components and a all-weather across-street banner.

so back to my problem, is it possible that the AC air is only redirected into the passenger air ducts?

__________________

Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Mine does that.
Seems to have a mind of its own, sometimes two vents have hot air and two have cold, with the A/C on...

Is it physically possible for the air to be ducted as you said on a 123?

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99 E300 TD -- sold
01 540i 6 spd

Sorry BioPower, I clicked the wrong button (edit instead of quote) and scribbled all over your post then had to delete it. This post was delayed by a period of maintenance on the MBShop website and a walk on the beach.

On your W210 the problem is the heater valve, I believe it goes by the name "duovalve" and it begins to stick. That, apparently, confuses the system brain and it loses its ability to relate valve position to temperature. I used to "recalibrate" the system by turning the defroster on and let it run full heat for a minute or two, then turn the defrost off. This would make the air conditioning work for a while, and the failure mode would repeat.

Someone else here had the problem too and removed the valve, disassembled it, and cleaned the bad stuff out. Don't recall the thread anymore and have not been able to resurect it. Maybe someone else can help. Otherwise it is a repair by replacement, and the unit is not cheap.

I am also not certain there are not ways to screw up the ducting on a W123 300D climate control box so that when the flapper actuators begin to fail you can get a similar set of symptoms. Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)