That's kinda strange, because you have 3 fans on the '94. Atleast one should come on to stop you approaching the red zone. As already stated the main 2 speed fan on the '94 has big fuses under the hood and the low speed winding should engage with the a/c or defroster on (below 47mph). If you are also able to run a scan with a code reader that low speed should also test out. I don't know how to self test the small pusher fan in front of the rad, but I believe it comes on above 228deg. A silly question maybe, but was the motor boiling hot when you hit the red zone; otherwise it maybe (hopefully for you) just a bad temperature sensor.