Report "1998 Ford Expedition. 4 wheel drive will not disengage. Switch is on 2wd but 4x4 light is on and front wheels are engaged. pulled #23 fuse but did nothing. Heard about replacing motor, acuator, vacuum acuator on firewall. Looking for a common issue with this truck and or hoe to test parts without just starting to replace parts without knowing if its the issue or not"