All my lights interior, dash, headlights have all started flickering on my 01 D. Has anyone else had this problem and fixed it? Hellllllp! Please

 

If it flickers with the vehicle running you should get the alterator/charging system tested. If it flickers with the vehicle off the problem could be a loose connection somewhere (like at the battery) or corrosion at the batt terminals.

 

Also could be a bad light switch or ground.