Blinker mystery.

I've got an 1989 Comanche 4.0L, and it does not like to blink. Here's the problem.

Headlights on: Front passenger light does not blink at all. Rear does blink, and so does the blinker indicator on the dash. The driver's side blinker will blink and is bright.

Headlights off: Passenger blinker very, very dim. Driver blinker is bright.

No Blinker, Headlights on: Passenger side marker lights bright, drivers side is very dim.

Both tail lights, and the dash blinker indicators blink at full brightness in all of these scenarios.

What's happening here?

Could be weak grounds at the lights. Can't carry the load.

i have seen front turn signal sokcets with bad ground contacts . also check to see if a bulb filament isnt blown and arcing against the other filament in the bulb

I found the problem. The previous owner had spliced in new sockets, backwards.