Thank you for your question, my name is ***** ***** I am a fully qualified vehicle technician with over thirty years in the trade, hopefully I can help.
One of the most likely scenarios is that the wiper relay is sticking, this is located in the multifunction control module and is relay number 10 (I have attached an image) the connections should also be checked for any signs of burning or water damage, both these things can prevent the wipers working. The module is located on the passengers side behind the glove box.
Another possibility is that there is a bad connection to the wiper motor itself or the switch operating the wipers.
When the wipers fail to work if jiggling the switch will get them to operate, then the switch is a possible cause, if this makes no difference and the relay as mentioned earlier is ok, then when they do not operate you should try moving the wiper arm slightly by hand to encourage it to begin operating, if it does than move, this would be an indication that the wiper motor is at fault. The wiper motor has a parking switch inside and if this is failing it can prevent the wipers from being activated.
I hope this answers your question but do please feel free to ask any further details by replying to this thread, if this does answer your question then please click accept and rate me, this allows me to continue, even
after clicking accept i can continue to answer your questions by replying to this thread