Just to update, got the new limit switch installed, and the furnace back in the motorhome. It seems to work properly, but have some concerns on the surface temperatures of the plenum, or case surrounding the heat exchanger. As I mentioned earlier, the furnace is installed with a bottom discharge. The new limit switch is rated at 170*, and the surface temperature of the top, and back of the case are in the 140*-160* range, but the sides of the case are reaching 275*, hot enough to burn your fingers.
There are partitions protecting anyone from touching this area, but thought I would feel the furnace before I reinstalled them. This is when I found it to be hotter than expected. Read the temps with a infrared thermometer.
Could this be normal??
Steve