Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Mark LT.
If your 4WD indicator light stays on but the system isn't engaging, there are a few potential causes. A common issue could be with the transfer case actuator, which is responsible for engaging the 4WD. If the actuator is stuck or faulty, it won't shift the system into 4WD. Another possibility is a failure in the vacuum or actuator system that engages the front hubs, often caused by leaks or blockages. An electrical issue, such as a bad 4WD switch or a blown fuse, can also prevent proper operation. Diagnosing the problem may require scanning the system for error codes and testing the transfer case motor and actuator.
If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!
