FRONT WIPERS ARE WORKING AND ARE NOT WORKING

MY FRIENDS SLM 206 PEUGEOT 1.4 HDI SEDAN WILL NOT WORK AND SOMETIMIZELY THE FRONT WIPER WILL WORK SOMETELY BUT I WILL CONTINUE TO WORK WHEN I HAVE BEEN STRESSED WHEN I HAVE BEEN TIGHT, I WOULD I LIKE I WOULD I LIKE I WANT TO HELP.