Headlight problem--very strange

I need some help.

I have an 89 Pickup that has problematic headlights.

For the last two months, the frequency of the headlights working as steadily diminished from 100% to 0% of the times attempted.
When they were working 50/50, they only came on when the truck was warm. The park lights and blinkers work fine.

Also, the weird part, if I turn the truck off but leave the headlights on for more than two minutes the truck will not turn over, seems like no juice to starter. After a few minutes with the lights off, the truck starts up.

I have replaced the relay and checked my battery cables and ground. Please advise with any help.

Thank you.

just check all the wiring that run to the lights. check on the fuses to.