Thanks for the message!
To answer your question, the slims fans on model number MMFS-ECL-90, the 1990-1994 Mitsubishi Eclipse Performance Aluminum Fan Shroud Kit are reversible if you reverse the wiring. If you are looking to make these spin backwards and push air, the black wire would need to be tied into the positive wiring, and the blue wire into the negative (ground) wiring on the car's harness.
Please keep in mind that if you plan on installing the fan shroud onto the back of the radiator (the engine side), you will need to have these mounted as pullers in order to "pull" fresh air through the radiator. If you plan on wiring these fans as pushers, they would need to be mounted onto the front of the radiator in order to "push" fresh air through the radiator.
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