2003 chevy express 1500 courtesy lights don't work

chevrolet
1500

#1

courtesy “dome” lights do not work when doors are opened or when dash switch is activated. Fuse (under driver seat) and Relay switch have been replaced. Can hear relay switch activated with dash switch. Lights work individual (toggle style ceiling lights). Dash lights dim with dash switch.


#2

The lights might be tied to a module that controls them and it may be bad.