Under the "steering lock" plate (special tool required for removal), there are two springs mounted to the turn signal switch assembly... One of yours has broken off.... the phantom sweep of the wiper is a common one with the s-series... The wiper switch has become real sensitive and activates the wiper usually any time the turn signal is activated... The wiper switch is a real pita to change out due to major disassembly of the steering column is required to get to it... If you wish to attempt it, I can email you the proceedure, but if you can find a haynes manual that has pictures, this is better...