both of these problems are one in the same it's the resister pack behind the control panel the wires will have melted together hence only working on no 4 with no heat .
remedy is take the panel of 2 screws at the bottom by the ciggy lighter and 2 at the top if it was regestered b4 96 (p) then take the control off and you will see the melted wires replace and rebuild .
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