Long freeway drive yesterday, stopped at a road-side rest, emptied my ash-tray and when I re-started my car, the vents would only blow warm air. Air conditioner setting, vent setting, all I can get is warm air. Could removing the ash-tray have knocked something loose. Has the climate control setting burned out? Oh, I've had this car for about six months, the cruise control has never worked for more than about ten miles during any given day. After I noticed the blower problem, I tried the cruise control and it stayed on the remaining 500 miles of the trip.

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Dave
1982 300TD Wagon 211,000 miles

I have had both problems in my 1986 420SEL. Sometimes I can get nothing from the vents but blasting hot air. Usually if I stop and shut the car off and then restart it works like it is supposed to. I understand quite often the culprti is the control push buttons. Also, for two years my cruise never worked really well, but lately it has been working fine - most of the time. I think the problem here is usually either the amplifier or some problem with the sensor up behind the speedometer, and occassionally using the wrong type of bulbs in your brake lights cause a surge or something to shut it off. (It is designed to disemgage when you put your brakes on, and it tells you are putting your brakes on by the brake lights going on). Have it checked out, I find these are minor inconviences, but I'm sure you'll enjoy your car alot more if you get them fixed.

JP Toronto

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Jason Priest
1986 420SEL

Okay, Had to test the theory that it would "correct" itself. Just took the car out and the climate control works just fine, however the cruise control is gone again. Does anyone have an idea of what to check for here? There must be some circuit common to the climate and cruise controls. My Haynes manual shows schematics for a 1981 and a 1983, but not my year - 1982. I can't see anything in common electrically.


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Dave
1982 300TD Wagon 211,000 miles

Do a search under "mono valve".....
This item is often the culprit of strange things happening with temperature regulation in climate control, especially hot blasts of air.
Any thoughts, Benzmac ?

Checked postings on Mono Valve, but the climate control seems to be working just fine now. The cruise control however, has given up again. Does anyone know if and how these two systems are related, as it seems they both will not work at the same time?

possibly vaccuum related ?

I don't think the two systems are realted. Cruise Failure on Benzes is common when they get around the age of our cars. I am pretty sure that the problem is usually the amplifier. Its a circut board and often the solder will crack causing poor or intermittent connections. They can either be replaced (around $250 for the part I think) or removed and re-soldered.



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Jason Priest
1986 420SEL