Check for a vacuum leak either under hood or under dash Check the operation of the vacuum controlled motors under dash Check the operation of the selector switch Defrost is the default position for this system
When you select the defrost setting , the air conditioning compressor will kick in and out to help dehumidify the air , that's normal to hear the compressor kicking in and out
If the outside temperature is about 50 degrees Fahrenheit ( 10 * C ) or higher and the defrost or floor and defrost modes are selected the air conditioning compressor will cut in and out as it dehumidifies the air ( that's normal )
The air conditioning condensor
The 1993 Ford Ranger air conditioning charge valve can be found on the top of the air conditioning compressor. The charge valve will be marked as the low pressure valve.
A 1985 Ford Ranger ( all engine sizes ) came WITH and WITHOUT air conditioning
I assume your talking about the air conditioning compressor kicking in and out when the " defrost " position is selected and the heat is on ? That's normal , it's to dehumidify the air and will only do that until the outside temperature drops to a certain temperature ( I would have to check the owners manual , I forget what temp )
The 1999 Ford Ranger low pressure air conditioning valve can be found on the air conditioning compressor. The low pressure valve will be labeled as the low pressure port.
There is a WOT A/C relay - Wide Open Throttle A/C relay - that shuts off the air conditioning compressor when you floor the gas pedal The wac relay is a solid state relay usually used to control the air conditioning compressor's clutch.
Should be R - 134a
The 1994 for Ranger pickup truck air conditioning system has a Freon capacity of five pounds. The air conditioning Freon should never be overfilled.
You most likely have a leaking heater core inside the truck.......
R -12