electrical problem

I have a 98 chevy blazer that the dash lights and interment cluster (including odometer) only works at night when u turn on the headlights by the switch. And the truck starts sometimes. I placed a piece of tape over the sensor on the dash for the auto lights( this made the dash, interment, odometer work) but now truck will not start. Ive been told its the inginition switch. Help Please.........:frown:

Cranks over and doesn't start, or doesn't crank over at all?