'87 Camry A/C Amplifier Schmatic??

I am trying to figure out the circuits of the A/C Amplifier on my 87 Camry....The diode on the board that gets the 12 volts from the heater switch gets HOT.... Burned out a diode (crispy) but I replaced it but still gets HOT.... Any source of a schmatic for this A/C Amplifier board???