Are you using logic gates to combine the signals, or trying to combine the pins?
If you are trying to combine the pins you will need diodes oriented the right way, PLUS a pullup resistor at the output (or a pull-down).
I suggest active LOW, diodes with cathode to pins and anodes joined, PLUS a pull-up R of a suitable value. 1kohm could be a good starting point.
If you are using logic AND gates, you should also use active LOW and a 2-input gate.
Cheers
Roger