try rechargeing your a/c it could have to much or too little
(added to answer) If the A/C blows cold at idle or while you are coasting, and stops blowing cold while you are accelerating or cruising under a slight load, it is more likely that you have a vacuum problem with the heater control panel, gates, or dash pots. If you ever hear a hissing sound coming from the dash, this is definitely the problem.
Freon is too low, or too high.
Games at High Speeds was created in 2003.
High pressure coolant is blowing out through a small hole in your heater core, it will need to be repaired or replaced. If it is warm out it might be AC refrigerant leaking.
Low speed relay bad Blower fan resistor Defective winding in blower motor
contaminants in system, over charged bad metering devise
Beacuse the temperature of the air falls by approx. 1 celsius every 100 metres climbed.
Because your motor is spinning faster at higher speeds causing higher rpm's
This is a partial answer. If the fan is blowing and air is coming out of the vent, but it's not cold, then I'm not sure what you can do. But, if the fan is blowing but no air of any temperature is coming out, then perhaps the evaporator coil has frozen. This can happen especially if the thermostat has been set for a temperature much cooler than the outside temperature. One way to check for this is to look to see if there is ice on the insulated copper line coming from the AC unit outside. To fix this problem, simply turn off the AC for a few hours. Turn your blower fan on using the manual override switch at the thermostat. This will help melt the ice on the evaporator coil. After several hours, check to see if you are getting air from the vents. Once you are, turn the AC back on--just not so low this time. (Or is it not so high?--Set the temperature in the range recommended by the manufacturer.)
Winds in ice caps are typically strong and cold, originating from high-pressure systems and blowing across the flat, icy surfaces. These winds can create blowing snow and lead to the formation of snowdrifts, contributing to the harsh conditions in polar regions.
Cose the high vents in the winter and low in the summer..
A loud knocking noise in the motor of a car at high speeds is most likely the engine. There could be another issue with the transmission if the knocking only happens at high speeds.
If the AC was working well yesterday and blowing cold, however, today their is no air being released, the AC could have been too high for two long. The AC tends to freeze up and has to be turned off for a while until thawed. If the blower motor and resistor needed replacement they may have officially blown and need replacement in order to work at all.