Chevrolet Repair: 96 astro fan swithc, loose wire, fan switch

Question
My fan switch does not work on high, but works on all the other settings. At first sometimes when it didn't work on high you could turn the engine off and then back on and it might work again. Now it doesn't work at all except on all the ohter settings, NO HIGH

Answer
If you have a DVOM or a test light, check for power at the blower when on high.  Probe the wires and see if 12V present.  If so, check for conductivity at the switch in all settings.  

Loose wire?  Or bad switch.  Or bad blower motor.  If not power present and playing with the ign switch works, it may be related to ign. switch contacts.  On lower speeds, the current must be spent on a capacitor.  When high speed, it can be direct battery voltage.

when it is the capacitor/resistor, it is usually the opposite problem.  No lower speeds and only high.