My 1999 Escalade has wiper issues. The wipers will turn on, but sometimes when you hit the "mist" setting instead of wiping once or twice they continue running for a minute or two. Sometimes when you put them on intermittent, they switch to low speed. Sometimes the fluid "squirters" on the front work and sometimes not. The rear wipers occasionally work, but most times not. Not sure if they are related. Anybody got any suggestions?