Aside from the commonly posted issues (radio popping on randomly and the heater running randomly while the key is out of the ignition) my speedo started acting weird. Taking a long trip, it conked out at 70 mph. My cruise control was directly affected, bucking/ shifting when the speedo seziured. I took it off cruise, and soon after the speedo stopped working period. 75 miles later, I got to my fishin hole, disconnected the battery, caught tons of croaker and spot (buddy nabbed a 25" Speckeled Trout), and drove home without incident. Any ideas on what the issue is?

 

Is this for the F350 in your signature? This is a Superduty, not a "Large Truck" so I will move your post to the Superduty forum.

But in the meantime, it sounds like the VSS (sensor on top of the rear end) is bad. Common issue.

The other stuff sounds like the GEM connector is wet.

 

Thanks. I'll look into the VSS sensor.