I have a 1996 Ford Ranger 4x4, 4.0L. The passenger turn signal is blinking rapidly. The front passenger blinker is flashing rapidly; however, the rear passenger light is not working. The bulb looks good and the fuse is fine. I have a feeling that I've got a wiring issue somewhere. Any ideas as to location or a systematic process to locate the issue? Thanks.

 

Well, after looking at the fuse, bulb, and wiring harness for obvious issues, I woke up this morning and found that the turn signal now works fine. Gremlins. I'm sure it's a wiring issue somewhere. Now that the blinker works, I have no way of troubleshooting.

 

Welcome to the forum

Flashers work by heating up.
There is a bi-metal piece inside the Flasher that changes shape when heated, this clicks the Flasher(relay) open(bulbs off), then bi-metal piece cools off and relay closes(bulb on), heats up(off), cools down(on)

The heat comes from electricity passing thru this bi-metal piece.
So the 3 bulbs on a turn signal circuit, front, back and dash board bulb, are the Load that heats up the flasher.
If load increases, adding trailer lights for example, you may notice turn signal flashes a little faster, heating up faster because of extra bulb

No flashing could be no load, bad bulb or bad flasher

People often install LED bulbs now, these use less electricity so less load(heat) at the flasher, so it may flash very slow or not at all, resistors are added to get more load or they switch to LED Flasher which needs less load to flash


Your fast flashing means something increased the Load in the circuit, could be corroded connection.
Look at trailer wiring, it is often the source of turn signal issues or blow light fuses, because it is exposed to water intrusion

 

I have a fast blink on the right turn signal which shows on the instrument panel. The back signal actually flashes, but the front does not. I've replaced the bulb in the front twice in hopes that it was just the bulb, but that does not fix the issue. Ironically, it only does this when the lever is fully engaged. I can hold it short of the engaged mode and both signals (front and back) work just fine. Once I engage the lever all the way, it flashes rapidly and only the rear bulb flashes. I have a 2010 Ranger XLT

 

Welcome to the forum

Multi-function switch has an internal short going by your description of holding it from locking.

Flashers work by heat, they have a bi-metal arm inside, as it heats up it separates the connection, then cools down and reconnects, then repeat

If you increase the Load the arm heats up faster, so faster flashing, you may notice this when you have a trailer hooked up, more bulbs so higher load so slightly faster flashing.

If you install low watt LED bulbs then it may not flash at all because arm never gets hot enough, lol, not enough of a Load.

So from your description it reads like with turn signal arm push up slightly it works but when pushed up all the way it is shorting out, high load, fast flashing
Does the dash turn indicator work same as signals?

Long shot would be to check trailer wiring, but that wouldn't explain the turn signal lever issue

 

Try jiggling the socket. if its anything like my truck it sometimes works and sometimes doesnt.