Originally Posted by Route 66
Bad grounds have probably caused more electrical problems than all of the other problems combined.
Dirk, You're absolutely right. Now put this concept into thought, the ground circuit is a 50% partner in anything that flows in a direct current circuit. Assuring connectivity here is often the easiest thing to do since once you ground the chassis there are hundreds of points where you can pick up a ground but how that ground. Assuring connectivity to the ground where ever it is critical in order for the attached equipment to function properly.
On the back of my motorhome, I have a ground that comes from the front of the vehicle to the rear and there is a ground on a separate connection that goes to the Pollock plug. The ground that came from the front was attached to a welded stud. When I went to verify that attachment and just touched the wire, it practically fell into my hand as I touched it. The repair involved cutting and crimping on new connectors and joining both of those ground to a common point.
Lesson learned here is a wire may visibly show that it's attached however any diagnosis requires that a hands on inspection is required and if that's worth the effort, remove the ground connection, inspect the connector, clean and restore the cable. Try to improve on the ground by using a serrated washer. The washer bites into the metal.