What freon goes in a 1990 Dodge Dakota?

1993 jeep Cherokee uses R12. But, if your vehichle has been upgraded it would be R134a. Look at your compressor, located on the mid lieft front side of the engine compartment. If it's OEM it should tell you what type of refrigerant is used. Also, you can look at the engine compartment sticker, located drivers side, against the fire wall.