Intermittent exterior lights and gauge cluster problems

Hi I have a 72 Mach. The headlights and tail lights, side markers, come on and off intermittently and different intervals at different times, sometimes headlights only sometimes tails and side markers only also the gauge cluster flashes intermittently and randomly all after about 10 minutes of driving time. Thoughts?

I have researched, ground wires, engine strap grounds, and bulbs themselves with no solution.

Also what does this green wire near highbeam switch go to? It’s only about 4inches long off the harness.

Thanks!!

The green (light green/ red dashes) wire connects to the parking brake switch if you have the optional convenience group.

All of those intermittent signals appear to come from the headlight switch...check your connections there and if no help, replace the switch.

What Midlife said...

If you've upgraded to halogen headlights, you may simply be drawing too much for the headlight circuit breaker to handle. I ended up running a relay harness for my Cibie H4 headlights and no more problems.

+1 on the relay