In my buggy the radiator is mounted behind the seats and it blows hot air through the fins and toward the driver/passenger. That's great sometimes but other times it would be nice to reverse the flow to suck through the fins and blow toward the rear of the buggy.

Is it ok to have the fan suck like that or does it need to blow?

just reverse the wires

I have mine wired on a 2 way switch, Relays on both, Taurus fan, definitely works better as a puller, but does the trick just fine as a pusher

there should not be a problem with it push or pull it still got air going though it :D

I thought for sure that everybody was going to say not to do it. I'll put this on my todo list.

What fan are you running? Depending on the pitch of the blades, it might work equally well in both directions, or it may not work as well running in "reverse". Or it will work, but just not as effeciently.