I have a 1990 ranger.. when I turn on the lights the front runing lights come on but the rears do not.. if i hit the brakes the brake lights work if i use the turn signals they all work and the revers lights work .. so what would cause only the runing lights not to work.. even the license plate lights work. i replaces all the bulbs and checked all the fuses..

 

Since both running lights are on the same wire it has to be a wire problem but to be on the safe side, start by chkg the bulbs, then the sockets and make sure they are in good order and clean.
After that start tracing the wire forward toward the cab and see if there are any pinched or broken areas in the wire.

Not totally sure on the 90 Ranger but if all is OK from the lights to the cab, there has to be an interface that is having a problem.

I had basically with a ’95 Ranger XL, and it ended up being the Multifunction Sw inside of the steering column, part of the directional system sw.

Have you hit anything under the truck lately, changed anything or added anything ?
All things that may have changed or pinched a wire.

When you are looking under the truck chk for a broken body mount, may have pinched a wire.

Just thinking out loud so luck to ya.

 

As Scrambler82 eluded, the park and license plate lamps share the same common power feed (via a splice at the rear) and share the same common ground.

I’d start by checking the obvious, damaged harness, trailer wiring (if present), bulb sockets.

If those check good, you’ll need to follow the wiring back to the splice where the park and license plate wiring split.

 

I didn’t think of that… shorter wire to trace.


Toomanycars,
Did you put a trailer hitch on recently ?

 

found the problem and fixed it .. About half way up the box some one had spiced into the brown wire with one of those blue crimp and add a wire (crapp) things and the wire had broken there .. I got rid of the (crap) added a small section of wire with solder and shrink tubing and its all good now ..

 

Figured it had to be a wire break...

Good that you got it fixed...