my interior lights blink on and off intimately -it just started i have owned the truck for three years . ex; driving to work-heater/ac on defrost high speed-cab lights start to blink-dim bright, dim-bright-slacken back on the accelerator and light stops blinking-turn down the heater/ac blower down one notch ,the lights stop blinking---what do y-all think the problem might be

 

Probably the door switch. Try pushing it manually and see what happens. If you do it slowly you might notice the lights flickering. If it does that, you might try brushing nail polish or something else to build up the surface of the switch a small amount and see if it helps. That'll make the door push the switch in a tiny bit more when closed, which might take care of it.

Mike