I am seeing 1.45V on the anode side of the zener and 0.7V on the cathode side. Since the CD74HC4067 is hooked up to the cathode side of the diode, I'm also seeing 0.7V there. If I hook up the CD74HC4067 to the anode side, I see 1.45V there.
I was expecting to see 5.0V-0.7V=4.3V at the anode side of the diode, why am I not seeing that?
If I just connect the diode from 5V to ground, I see 4.3V when it's forward biased.
Any help would be appreciated.
Edit: rectifier diode, not Zener.
Fix found! I had to disconnect GPA1 (accidentally still had it connected).