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Why won't my air-conditioner work when I'm driving uphill?

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DEAR TOM AND RAY:
HELP! I HAVE A PROBLEM THAT OCCURS WHEN I'M ACCELERATING UP A HILL IN MY DODGE ARIES. THE COLD AIR FROM THE AIR-CONDITIONER WILL STOP COMING OUT OF THE DASHBOARD VENTS, AND START COMING OUT THROUGH THE FLOOR VENTS. WHEN I GET TO THE TOP OF THE HILL AND STOP ACCELERATING, THE AIR SWITCHES BACK AND COMES OUT OF THE DASHBOARD VENTS AGAIN. WHAT'S GOING ON?
MARGARET

TOM: THAT'S AN INTERESTING PHENOMENON, MARGARET. WE THOUGHT IT MIGHT BE ANOTHER INNOVATIVE MOVE BY CHRYSLER DESIGNED TO MAKE SURE YOUR FEET DON'T SWEAT FROM ALL THE EXCITEMENT THIS CAR CREATES GOING UP HILLS. BUT IT'S ACTUALLY A CHRYSLER MISTAKE. UNDER CERTAIN CONDITIONS, THESE CARS SUFFER FROM LOW VACUUM.

RAY: WE'RE NOT TALKING ABOUT UPRIGHTS, CANISTERS, AND BEATER-BRUSHES, MARGARET. ENGINES CREATE NATURAL VACUUM--OR SUCTION--WHEN THEY RUN. THAT VACUUM IS USED TO OPERATE--AMONG OTHER THINGS--THE VENT DOORS IN THE HEATING AND COOLING SYSTEM.

TOM: VACUUM IS ALWAYS AT IT'S LOWEST WHEN THE ENGINE IS UNDER LOAD (WHEN IT'S WORKING HARD). SO YOU WOULD EXPECT IT TO BE LOW WHEN YOU'RE ACCELERATING UP A HILL ANY?WAY. BUT YOUR ENGINE'S VACUUM DROPS SO LOW UNDER LOAD THAT IT CAN'T EVEN KEEP THE DASHBOARD VENTS OPEN.

TOM: IT WON'T DO ANY DAMAGE TO THE ENGINE OR THE VENTILATION SYSTEM. BUT IF IT BOTHERS YOU, YOU MAY BE ABLE TO HAVE YOUR DODGE DEALER INSTALL A "VACUUM AMPLIFICATION" KIT WHICH SHOULD IMPROVE THINGS. MAKE SURE YOU GET THE OFFICIAL DODGE KIT, THOUGH. WE'VE SEEN SOME CHEAP IMITATIONS THAT JUST GIVE YOU A DUSTBUSTER AND SOME DUCT TAPE.
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