I am probably missing something but give this a shot.
Code:
@ __config _CONFIG1, _INTRC_IO & _WDT_ON & _LVP_OFF & _CP_OFF

INCLUDE "modedefs.bas"
ANSEL = %00001111 'set RA0-RA3 as analog inputs
OSCCON = $60 'Sets the internal oscillator to 4 Mhz
CMCON = 7 'Comparators off

ti var byte
ti = 50 '20 MILLISECONDS DELAY' 
A VAR word
B VAR word
C VAR word
D VAR word 
TRISA = %00001111 
TRISB = 0 'TURN PORT B as outputs but RB1 WHEN USE ICD FOR COMMUNICATION

'* * * * * MAIN PROGRAM START HERE * * * * * * * * 

PAUSE 1000
Serout PORTB.1, 0, [254,1] 
Serout PORTB.1, 0, [254,2]
PAUSE 20

READSENSORS: 
ADCON1 = %10000000 'SET FOR 10 BITS 
ADCON0 = %00000001 'Turn ON CHAN 0 
GOSUB ADCON
A.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR 
SEROUT PORTB.1 , 0, ["Ch 0= ",# A.LOWBYTE]
pause 20
ADCON1 = %10000000 'SET FOR 10 BITS 
ADCON0 = %00001001 'Turn ON CHAN 1 
GOSUB ADCON 
B.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, [" Ch 1= ",# B.LOWBYTE]
PAUSE 20
SEROUT PORTB.1,0,[$FE,$C0]
ADCON1 = %10000000 'SET FOR 10 BITS 
ADCON0 = %00010001 'Turn ON CHAN 2 
GOSUB ADCON
C.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, ["Ch 2= ",# C.LOWBYTE]
PAUSE 20 
ADCON1 = %10000000 'SET FOR 10 BITS 
ADCON0 = %00011001 'Turn ON CHAN 3 
GOSUB ADCON
D.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, [" Ch 3= ",# D.LOWBYTE]
PAUSE 1000
Serout PORTB.1, 0, [254,1] 
GOTO READSENSORS ' PROVISIONAL LOOP TO CHECK THE A/D CONVERTION.
'* * * * * * * * * SELECTING THE MOTOR MOVEMENT * * * * * * * * 

'* * * * * * * * * MOTOR'S MOVEMENTS SUBRUTINES * * * * * * * * 
ADCON: 
ADCON0.2 = 1 'IT'S ONE TILL IT READS
WHILE ADCON0.2 = 1 : WEND
RETURN 
END
This is what I am basing the sequence on. From the data sheet.
1. Configure the A/D module:
• Configure analog/digital I/O (ANSEL)
• Configure voltage reference (ADCON1)
• Select A/D input channel (ADCON0)
• Select A/D conversion clock (ADCON0)
• Turn on A/D module (ADCON0)
I am pretty sure this sequence needs to be followed. I am not at the shop so I can not test your code now.