...(The below is to help guide you...we presume you've checked your fuses and that the wipers do work, only the intermittent function is not doing it's job)......
Do you have the Wiper switch that has the "roller" or a multi-point switch that controls the time between wipes on the switch arm or on the Dash?
If it's on the Arm, you may have a bad switch - not the switch itself but the electronics in it that handle that pause.
That timer may be bad - the intermittent function needs to be able to know which level of time - so it uses a rheostat (potentiometer or variable resistor) in that arm that the "roller" or even the muti-point setting - these work to change your intermittent wipe times.
This communicates back to the wiper motor - which once one wipe is done - the thing is supposed to "park" until the timer tells - bumps it off-park to force the motor to cycle to move the wipers for a small length of time until the pause pulse has elapsed and the motor it left to think it needs to park itself and completes the cycle.
So if the other settings on that arm work, then the issue is with the switch - the rheostat is dirty and you'll need to take apart that switch to get at it - it's possible and it's SMD (meaning the technology is unique but common) and the composite used to make it variable is more than likely destroyed by time and age.
So you'll need a new one.