Crazy lights..searched already.

It's one of those infamous blinker problems, except I haven't found mine anywhere else in the world...
It's a 91 4.0 (91 and a half really, if it makes any difference), and my left side is rebellious. When I have my headlights on, the left arrow on the dash is on, like the light is out. All of the lights are on outside when the headlights are on. It will not blink left, the dash arrow stays on, my front left parker doesn't flinch, the left front side goes off and my back left stays on. When hazards flash, it flashes the right side and the back left, then the front left will blink. The front left parker/side is substantially dimmer than the other side always. And my cruise is out too, if it's related I don't know...

try replacing the socket had a similar problem with my 87 new soket work fine now.

or the flasher relay

bad groung replace socket and call it good

Sounds like a blown bulb to me...1157NA