Door lock problem on Ford 2015 E 350 Chassis for MotorHome

you could have a weak battery in your remote control or your having ignition problem's

Well, there isn't a remote control. As I said 'on the drivers door, when I select(toggle switch) to lock doors...

My E350 RV just started doing exactly what urs is doing. Did u figure it out?

Yes I did. My problem was 2 fold. The key in ignition chime would be active any time the drivers door was open, without a key in ignition. This issue affected the door lock function. I traced the problem to a wire from the clock spring that went to a connector with a contact activated by the ignition switch. The connector was damaged but, found a way to make a work around. If you have this situation you will have to install a new clock spring because you can't buy the connector. If you don't have this issue, you probably have a bad door switch... BTW, I 'm a electrical engineer. Spent many hours tracing through wiring diagrams to fix my problem.. ....

This is my problem as well. But what is a clock spring and where is it located?

The clock spring is in the steering wheel. If you don't have any experience working in that particular area it could be dangerous. Suggest you take it to a mechanic.