I am having the exact same problem with the instrument panel not working, or the fan not engaging. Everything else electrical on the vehicle works. I also have a 1994 Ford Mustang GT convertible. I have replaced the Instrument cluster with another one. Gauges still not work, all I can get is the lights to light up behind cluster And the right signal works. As with the fan I turn on the AC, the fan should turn on but it is a no go. If you have any information on how to troubleshoot or fix this it would be appreciated thanks.