Is it possible to hook up the heater hoses backwards on a 1992 Ford Explorer?

Yes, it's possible to hook up the heater hoses backwards on a 1992 Ford Explorer. However, doing so will prevent the heater from working correctly. The water will simply circulate through the engine without passing through the heater core. You might even see some unusual behavior like the engine overheating slightly faster than normal as the coolant flow is altered.