The ammonia odor could be from a windshield wiper fluid leak, or you could have a leaking heater core, which can fog up the windshield. Hard to say without seeing the vehicle, let us know what you find out!
Fogging yes heater core, ammonia? Sounds like what you said, wiper fluid. To the visitor, anyone who knows anything about any vehicle, knows not to flush a cooling system with house-hold water pressure using a T on the Heater lines, which always causes premature heater core or water pump gasket failures. However, since the Samurai was discontinued (Excluding the not imported Jimney) there has been no Suzuki's with washer fluid lines inside of the passenger compartment. Wondering what could possibly be leaking inside to cause the ammonia smell?