The following is intended *only* for suitably qualified technicians.
The switches go intermittent after a while. I tried cleaning them to no avail. So I decided to fit alternat switches which are available at Jaycar for a couple of dollars. See photo. The method I used is shown in the video. You may need to make the switches waterproof with a little silicon sealant.
I wish these cheap switches would come with a chamfered thread that could accept a locking collar. This collar would have a tang that fits inside a drilled hole in the panel, thereby preventing rotation and loosening during use.