I believe Newmar used the PTL Pos-a-Loc . It's the mechanism that keeps the front door in the open position and your description seems like a common problem.
Here's a tutorial that has been posted on the forum in the past that possibly can help you adjust it:
PTL POS-A-LOC CABLE ADJUSTMENT
You might do a search or post a question about it over on the Newmar Owner's Forum (
go HERE) as I may be incorrect as to your model using the pos-a-loc.
Just found this from Newmar on the installation of the pos-a-loc if it will help further:
https://comnet2.newmarcorp.com/insta...ages/PTLLI.pdf