New to this forum, first post.

I have an '05 2500HD

I am having a problem with the Amp Steps and the interior lighting.

Drivers door: Lights and steps always work
Driver side rear door: Lights and steps sometimes work
Passenger side front door: Lights and steps mostly don't work
Passenger side rear door: Lights and steps never work

Ive heard there is a motion sensor in the door latch? Is this true?
If so Im thinking Im gonna change all four

Does anyone know where to get them?
Ive checked Carparts.com and they don't seem to be the ones that have a sensor.....??

Thanks for the help in advance

Nick