I went ahead and checked out what we have for your 2018 Heartland RV Pioneer Travel Trailer, and the closest I was able to find is the:
-Low Profile LED RV Tail Light - Stop, Tail, Turn - 9 Diodes # RVSTLB60 for the passenger side, & the,
-Low Profile LED RV Tail Light w/ License Bracket # RVSTLB61 for the driver side.
These lights measure 8-11/16" long and 3-3/16" wide. view full answer...
I took a look at what we have for the Westin Molded, Lighted Running Boards # 27-0015, and the Replacement Lenses and Housings for Westin Molded, Lighted Running Boards # 27-9904 actually comes with a rubber seal pre-installed so there is not a rubber grommet for this.
If you also need replacement bulbs, you can use the Replacement Bulbs for Westin Molded, Lighted Step Boards # 27-9905.
If you're referring to something different, let me know and I'd be happy to see what we have. view full answer...