I have a problem that just started today with the tail lights on my 2004 Ranger (Reg Cab 2.3, 5-speed, shortbed, cheapest truck sold). Tail lights and brakes lights worked when started up to go to work. Put turn signal on and the flashing started to get weird irregular frequency, and eventually the fast blinking dash indicators. Great, I thought must have lost a filament. But then determine it does same fast blinking on both left and right turn positions. So then I am really wondering what is going on.

A guy at stoplight near work gets my attention and says I have no lights, either running or brakes. Fortunately no cop to hassle me about the lights and get to work.

So at home this evening I do some checking and here are some conditions:
1. Checked and even replaced both rear bulbs = no change in conditions
2. With parking lights on = have front park lights, have dash lights, no rear tail and do have license plate light.
3. With parking or headlights off = have very dim brake lights. Kind of like the brake lights are actuating the running lights?
4. Hazards flash normal speed (I presume, about normal turn signal speed), but same dim rear lights.
5. Ignition on, turn signal switch left or right = both rear bulbs flash quickly, same dim lights.

So any ideas what might be my issue? Maybe the multi-function switch has gone bad? I did not have time to do much more investigation. Tried searching the forum here and did not find anything same as what I am experiencing. Appreciate any helpful advice or where to start looking for the problem.

 

there is a plug at the rear of truck under the bumper,,,, sometimes it gets dirty or someone has put a trailor adapter on and didnt seal it good,,,, check it and clean it good

 

^+1 on checking the trailer lamp plug & where it plugs into the vehicle wiring harness.
Kinda sounds like you might have a faulty ground. Here is a link to look up the wiring color codes Search Wiring Diagrams
If you have or can come by a ELM scantool & run FORScan or the like software on the viewing device of your choice, it can likely scan the body computer to give you a trouble code clue that could help focus your troubleshoot.
It found body code clues in the GEM & ABS systems that led be to the root causes of my ABS light on, no cruise control & intermittent power window problems. So, for about $25 bucks delivered, it more that paid for itself on the first trouble shoot, by getting my ABS trouble shoot focused & back on track with a successful ending & provided Body code clues I didn't know I had, that led me to find & fix my power window woes at no cost!!!! A Danged good bang for my bucks & a Must Have for our electronic tool box now days imo.
More thoughts for consideration, let us know how it goes.

 

Winner winner chicken dinner! I found that plug, it seemed a bit loose. Opened it up, cleaned it, and reconnected a few times to help clean the contacts. Made sure to fully seat it. All lights back to working like they should! I owe KF4EYR a beer

 

good deal it some times just something simple,,

 

Ok good find, fix, feedback & ^+1 Good call KF4EYR.