I am remodeling my bathroom with new ceiling exhaust fan/light combo. I am having trouble hooking it up. I have 2 lines coming, one is a 3 wire and the other is a 4 wire with red wire for switching purpose on fan. I have a double switch on the wall to control both the light and fan indepently. I have hook up the white wires together and the green wires together. I hook up one black wire to the red wire for exhaust fan and then I hook up the other 3 black wires together, but when I hit the circuit breaker pops, I have tried other ways to no avial, can anyone help with suggestions.