When using the vacuum (25812) with the powermate,

Check your lower and upper wand connects for pinkish or blackened evidence of burning. All connections should be shiny clean brass. Polish with wet dry # 600 paper or a scotch abrasive dish pad.

If the junior runs, with its tighter, cleaner less used connections it is very likely the wand connections and mating component, either the hose handle or power head elbow are also burned or badly worn. On a Kenmore, due to the weight of the head and mediocre design they wear in pairs and should be replaced in pairs. You can get some electrical parts thru a Whirlpool FSP parts center or a Panasonic dealer if you take in the matching pieces for clarification