On our trailer, they are held on with upside down "L" brackets that are screwed into the wall. The valance sits on the bracket and is held on via a screw from the underside. It is necessary to remove them to work on the blinds or remove the blinds. It is not necessary to remove the screws into the wall or remove the bracket.
I have removed mine several times to replace the strings in the blinds. To get the Valance off, I raised the blind about half way and then stuck a long screwdriver up under the valance to take out the screws (2). The screwdriver I used was at least 12 inches or more long. Found it at a flea market in Florida many years ago.:)
Removing them was the easy part. Putting them back was a bit harder as you had to guess as to the proper placement of the valance in hopes of getting the screws back into the previous holes in the wood. I found the best way was to first put a screw up through the bracket, hold it there with long screwdriver, and then place the valance on top and fish around for the hole and start the screw in. Then repeat on the other end of the valance. When you get that screw started, finish the job on that end and then move back to the first screw and tighten that one up.
Doing it that way will eliminate a long frustrating time trying to fish the screw into the hole from below and you can't see what you are doing.
Found this out the hard way!:R
Hope this helps you out.
๐Barney
2004 Sunnybrook Titan 30FKS TT
Hensley "Arrow" 1400# hitch (Sold)
Not towing now.
Former tow vehicles were 2016 Ram 2500 CTD, 2002 Ford F250, 7.3 PSD, 1997 Ram 2500 5.9 gas engine