So I'm puzzled by this one but hoping to get help. 2000 F350 dully with turbo diesel with lots of miles.

The problem is that when you turn the headlights on in both parking or headlight setting, the dash board lights that illuminate so you can see how slow you are going at night flicker, almost like pulse on and shut off in a constant frequency. So you get like half a second to see your speed, then nothing until 7-9secs later it will flash again. The exterior parking , marker and headlights all work just fine and stay illuminated as they should but just the cluster lights are having their issue. The radio also does its dimming thing too but flicks with the dash lights frequency.

I've just tested out two light switches I picked up from the junk yard and it is still doing the same except the time between the lights flashing on has shortened...kinda. I've also looked through all the wires I can see with the front dash apart and checked the wiring in the flatbed side too but still coming up empty handed. I can not hear a relay clicking from the cab or the engine bay when the lights are flickering. What am I missing?

 

You say you checking the wiring to the instrument cluster? A loose connection is what it sounds like to me.

 

Yeah, I pulled out the cluster and checked that out, cleaned up connections but still same. Is this something that can be traced with an OTC genisys by chance?