OK... That is the aux fan sw , but very seldom does that sw go bad..people often incorrectly change it b/c they think it goes bad, but the real reason the fan does not come on is b/c they are short of refrigerant [ not allowing high side to get to trigger point of the sw]
..anyway, gauges would be needed for pressure readings.
Did you use an original R12 EV?
..also, You may have overcharged...