What type of refrigerant goes in 1994 Mazda b 3000 pick up?
It should be R134a the fittings high and low pressure line should be large in size.Your model year should have a sticker under the hood unless it is gone stating this.The early 90s stuff like yours should be the newer air condition product.Any local shop can point this out and even the air condition compressor may have a decal stating the refrigerant that should be used.
In vapour compressor refrigeration system the low pressure and temperature vapour refrigerant from evaporator is compressed. where it is compressed to a high pressure and temperature. From compressor refrigerant goes to condenser where where it changes the phase. from condenser refrigerant goes to evaporator through expansion device.
Is it a new or an old window unit? Assuming your looking to refill it I will assume it is an old window unit which most likely uses R-22 refrigerant. R-22 is an ozone depleting refrigerant that is being phased out but should be available until 2010. There should be a label on the window unit stating which refrigerant is used.