wipers intermittentw/ fuse pulled

My '91 Voyager 4 cyl. started having instument panel problems like the warning lights coming on and going off, fuel gauge on-off, speedometer on-off, etc. But the weirdest is the wipers wipe very irregularly one swipe at a time when they're not even turned on, not rhythmicaly as when in intermittent mode - even when I pull the wiper fuse. The only thing that stops this is pulling the gauges fuse, but then of course I'm without gauges altogether. It began after an aftermarket cruise control was added. I don't know that they're related , but I heard sometimes they are impoperly installed by fishing blindly for a ground wire in the steering column, pulling it out and using that ground. Is a bad ground the first suspiscion? Bad grounds seem to cause all sorts of problems.

Rob