Sealing gap between front cap and frame

[Gegrad]

So last week went in to prep for first trip, turned air on and insulation came out of the vents; crap, have a mouse. Ran the air for several hours and cleared out all odors. Checked everywhere (pulled furnace cover, electrical cover, hot water heater area, all cabinets, front hatch) and no evidence of mice anywhere but the ceiling. Searched threads on here and ran the high frequency audio noise last week in the middle of the trailer and stuffed fresh cab in the vents.

Went camping this weekend and in the middle of both nights could hear the scratch scratching from inside the front cap. Only opening I have is the 1/4" gap where my front cap stops short of the frame. All my drain holes are sealed tight with spray foam and my coroplast is tight everywhere else. This evening started running the high frequency audio right up in the bedroom close to the cap; also stuffed a bunch of fresh cab up there. I also set some snap traps on top of my battery and frame. Came inside for an hour and a half, went back out and sure enough snapped a mouse from the trap on top of the battery cover. Of course right now I don't know if that is one from the front cap or somewhere else. So I will continue to do that for a bit.

My question is, assuming I can get them all out, should I do anything to seal the gap between the from cap and frame? Or does that need to be open for air ventilation? If so, any ideas on preventing more unwanted visitors?

[JRTJH]

They may have got into the trailer through the air conditioner. It's just a "foam housing over the air box"... Once inside the plastic housing, they can chew through to the ducting fairly easily. Once in the ducting, it's an open shot to anything above the luan ceiling boards....

[Gegrad]

They may have got into the trailer through the air conditioner. It's just a "foam housing over the air box"... Once inside the plastic housing, they can chew through to the ducting fairly easily. Once in the ducting, it's an open shot to anything above the luan ceiling boards....

Interesting, had not thought of that John. Hmm. So any way to prevent that in the future?

[JRTJH]

Do you cover your trailer? or put one of those Dometic A/C covers on the rooftop unit? If so, they are "open invitations" to roof access for mice. If not, are there any overhanging trees, rafters close to the roof or ropes, cables they could climb up to access the roof? I haven't seen any evidence that mice can climb the FILON sidewalls, but they can use the awning side rails or such as a means to get up there.

I don't know of any "easy method" to stop them from climbing through the air conditioner, but I've put "baited poison" in a couple of units (reluctantly, because a dead poisoned mouse becomes food for other animals that then ingest the poison)… But, protection of your investment determines how far you want to go to preserve it.

[Gegrad]

I do not cover my trailer or put an AC cover on it. I also don't have any trees, cables, or anything near overhead my trailer. It sits about 15' from my house and deck out in the open. That's the main reason I thought they were getting in from the front cap gap.

[Frank G]

I find it much easier to manage a Neighborhood cat or two than put up with the mice.