Electric problem

Hi, I'm Bogi, one of the auto experts on RepairPal's Car Genius team! Sorry to hear you are having issues with your E-350. The fact that shaking or wiggling the negative wire used to get it running is a pretty big clue. I assume you are talking about the Negative Battery cable. If your connection at the battery is loose, or if it is loose where that cable connects to the body it can cause all sorts of issues. The cable itself could also have high resistance or be internally damaged. You also mentioned it “used” to work, which suggests it no longer is. It may be time to have a qualified shop that has access to factory wiring diagrams take a look at it. They will be able to figure out where the connection issue is and how to resolve it. Feel free to give us a call at 877-913-1554 if you have any other questions or if you'd like help finding a trusted RepairPal certified shop in your area. You can also copy and paste this link https://repairpal.com/auto-repair-near-me to locate shops near you.