I replaced my bathroom vent/fan with one from Camping World. Do a precheck with the existing wiring before you install & screw the new unit in place. My factory original vent/fan had a metal trim ring that the 16 - 20 screws went thru. This trim ring was used for the ground. The replacement vent/fan had a plastic trim ring, thus no ground for the fan. I had to install a ground wire for the unit to work. Don't know if this was a fluke or the 12v gods were testing me.
The vent/fan has been working great for the last 5 or 6 years.
Bob