I have spent many years as a field electronics service technician. I worked on yachts, houses, and some RVs. It has always amazed me had how mad a person gets at a peice of equipment when it doesn't work. Only to find out that a short cut was taken, or heaven forbid, someone made a mistake when installing something. If you find a blown fuse to a light and you replace it, and as soon as you replace it it blows again, do you keep putting fuses back in? Or do you go to the light and try to figure the problem. This may not be your forte, but you don't get this mad about something. One of the worst things for a tech to work on is an intermittent problem. Whenever it gets to the tech it works!
I can not, for the life of me, see that this many devices are bad. After some one gets something working, they don't seem to post the results. When I was a senior technician, it was my job to help the younger techs out. I can't tell you how many times they would call me and say "the autopilot display is dead". My first question always was "what is the voltage?" If they said anything other than a number, I hung up. They didn't check the basics. Most times the issue is a blown fuse, loose connection, bad ground, etc, easy fixes. Our TTs and RVs take a pretty good beating going down the road. Many of the DC wiring connections are less than desirable, IMO, in our new TT. Like I said in a previous post, I do not like butt (crimp) connectors. A terminal strip would be better but soldering and covering with heat shrink is best. I understand why butt connectors were used. Time, money, and skills play a big role. Please look further than the on/ off button of a device before complaining about it. And please, if you have trouble with something, please post results. That will help so many forum members.