The preheat on my Onan 7500 seems to have quit working just as AZ nights are turning cold! This is on my 04 Gulfstream, I checked the F-3 fuse and it is good, my question is does anyone know of a good shop in western AZ that could change the glow plugs? I looked and don?t see any way to get at it, afraid genset will probably have to come out, and that is something I could not do! Any help is appreciated and Happy Holidays to all!