Could be a couple different companies. I suggest you make a quick call in the morning to Heartland Customer Service with your VIN and they should be able to assist you. The number is 877-262-8032.
Please circle back here with the info you find so you in turn may hep the next guy. Thanks.
OK. I phoned Heartland and gave them the VIN number. Very helpful. Told me it was a Henge's Industries vent, model 7112-C. Then I phoned up Henges (via Google). Nice lady told me the lid was part number 90110-C1. She suggested I call a local dealer. I did so. They could get parts from Henges. This lady suggested I take off the current lid and bring it in and she would match it.
PROBLEM: HOW TO TAKE OFF THE METAL BAR THAT RAISES AND LOWERS THE FLAP. The hinge seems siimple enough, I just untwisted the end piece and it will slilde out. HOWEVER, THE BAR TO WHICH THE PLASTIC LID IS ATTACHED IS a different matter. The bar is attached to a short strip which has a semi-gear which forms part of the twist handle inside the bathroom. The short strip is attached to the bar via a groove which has a large hole at the end, which is obviously used to put the strip and bar together. Unfortunately, you can't unwind the twist handle enough for the strip end to get to this large hole in the bar.
The other end of the short strap is attached to a strong metal U channel that goes across the opening. The gear end of the strap is attached to the channel by a clevis pin. If I could take the clevis pin out, all would be OK ! Do I drill or push it out ? Any suggestions ?! Thanks.