Sorry, my mistake...
I did not see the data sheet and I have not used this Pic.
I read you need use AN3 as adc input and I assumed this was at Gpio.3.
It is at Gpio.4, then you need set trisio.4 as input and the correspondent pin at Ansel.
But Trisio.5 MUST BE CLEARED to work as output.
Greetings...
Ruben de la Pena V.