Question about 2002 Dodge Ram 3500 Truck
A low charge of freon, or a dirty evaporator, in the heater compartment that restricts air flow through the evaporator, will allow it to freeze up, and get covered with ice. Then NO air can get through it.
If it has been used in dusty country for 200,000, I would bet it needs washed out.
The condenser coil in front of the radiator may be bent and plugged with bugs and dirt, and grass seed, which will also keep it from working well, but I bet on the evaporator being dirty.
Is it possible to have 134a refrigerant rathr than r-12 then you can get a cheap pressure gauge at any parts store that will allow you to check the refrigerant charge to be sure it's still properly charged. These gauges usualy have color-coded ranges t show if the system is low, OK, or over charged. Keep in mind that this pressure reading is looking at the low-pressure side of the system and only shows you a valid reading when the compressor is running.
listen to referigerartion compressor! if it is "short cycling", - (cutting in and out rapidly)-- it should run about 60 seconds on hot day, engine "blocked" on gas pedal,- to keep at least 2 times normal idle speed (or slightly more)-- all the doors open, and a/c set on highest blower speed! Compressor should run about 60 seconds before shutting off! Top of dryer cannister should also have condensation forming on it , - and if fully charged it will "flash" frost just before it turns off! This is the big metal cannister standing right by the "heater plenum box" (it is about 2 1/2 incheds in dia. and about 7 inches tall)!
This is a "critical charge system and if a little too much or not enough freon is in it,-- it will work poorly, the lower it is the more often the compressor will turn on and off, - when about 1/2 pound off, it will cease working all-together!
At night the air is a little cooler, and the compressor running in shorter time "spurts' may still move enough freon to make the a/c cool somewhat! Also the air going through condenser (in front of radiator cools better with cooler air, so the freon may provide mo expansion when going through to cool somewhat better! This may be "throwing you off a llittle"!
This is not the best a/c system available, as it does not have "thermal expansion valve" like the "old timers", it has a brass pellet with a little hole drilled in it, - and when pressures on both sides are right it works, - but if a little off, it does not work! The thermal part of "expansion valve" adjusted flow so that it would work at least some when even 1/2 full of freon! Your system has about 7# of freon,-- but loose 1/2# and it is basically dead! This will cost WAY more in maintainance during lifetime of vehicle than the $30-40 they saved when making car!
Thanks for contacting Fixya
Posted on Jun 19, 2009
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Posted on Jan 02, 2017
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