I have a 99 3.0 with electrical issues. The speedometer and wipers work intermittently. All of a sudden without warning when I'm driving the speedo will start working for a while and the wipers can be turned on from the stock. Then those functions will disappear without any warning. When they are functioning if I try to turn off the motor it will run until I open the door. Weird huh? I got around to replacing the ignition switch today thinking that might be sending a message to other components to turn off. No luck with that. Any advice you can give about how to trouble-shoot this would be appreciated. I was thinking that a ground or relay might be bad, but don't know where to look.

Thanks,
Craig