A 1999 Dodge Ram Van doesn't use a speedometer cable. Instead, it uses a Vehicle Speed Sensor (VSS). This sensor is electronically connected to the speedometer and the PCM (Powertrain Control Module). You won't find a cable; the connection is electrical. The exact location of the VSS varies slightly depending on the transmission type (automatic or manual) and the specific rear axle configuration, but it's usually found somewhere near the transmission, often on the output shaft or attached to the differential.
To locate it, you'll likely need a repair manual specific to your 1999 Dodge Ram Van's year, model, and engine/transmission combination. A visual inspection near the transmission is the best starting point. Look for a small sensor with a single wire connector.
