I've got a 1994 Ranger XL 4X4. The turn signal works, but both rear turn signals continue to blink simultaneously even when the turn signal isn't engaged. The hazard lights work normally both front and back when the ignition is on or off. However, when the ignition is off, the rear turn signals stop flashing. But once I turn the key into the on position (without starting the engine) the rear lights start to blink.
I got a new turn signal assembly (multi-function switch) believing that was the issue - nope, same thing.
If I pull the fuse (#13) the blinking stops of course, but I've got no turn signal or reverse lights at that point, but it does help with driving around town without rear hazard lights blinking constantly (it doesn't affect the front turn signal lights).
I removed the multi-function switch and tested it with ignition in off position. The white/red stripe (hot) wire remains hot as it's suppose to (to feed hazard lights). the Light Blue wire which turns hot when ignition is turned on has no current - as it's suppose too with the ignition off.
With the multi-function switch removed from the steering column I used a low lever circuit tester and stuck the probe into the back of the harness without unplugging it.
I tested to see if there was any current to the front turn signals - none
I tested to see if there was any current to the back turn signals - none
I turn the ignition to on
I tested to see if there was any current to the front turn signals - none
I tested to see if there was any current to the back turn signals - yes (and they were flashing)
I tested to see if the turn signal would work with the ignition on (but the engine not started) and it doesn't, but the hazard lights do.
I turned the engine on and tested to see if the turn signals worked - yes, both right and left (at least on the front, but both rear lights continued to flash).
I thought the turn signal switch is like the switch on a wall. Unless you physically turn it on (as one does when turning right or left) there should be no current being fed to anything, yet there is a constant current being fed to the rear blinkers through the multi-function switch.
Just a side note - when I pull the Light Blue wire out of the harness that's plugged into the back of the multi-function switch and touch it with the low voltage circuit tester, the rear lights start flashing.
I removed the fuse and tested the slot with the circuit tester - it had current when the ignition was on, but not when it was off.
I put the fuse back in and tested the flasher relay - it was hot when the ignition was on, but not when it was off.
I removed and cleaned all the grounds that the wiring diagram said were present.
I checked all the bulbs and sockets for corrosion.
I checked for burned, spliced or grounded wires along the run from the tailgate to the cab and found nothing.
Am I missing something?

 

Welcome to the forum

Here is the exterior light wiring diagram for 1994 Ranger

The front signals and dash signals are on their own separate circuit.

Rear lights use different wires
The Light Green and the Orange wires coming out of the multi-function switch

A hazard flasher has power all the time, hazard switch is not part of multi-function switch but does use the turn signal wires in the multi-function switch
Turn flasher only has power with key on
The flasher gets the power but won't flash until a Load is applied to it, a Load is a light bulb that is grounded.

See which flasher is "flashing" when rear signal are on.

Also bad trailer light wiring can cause some oddball issues with truck lights

 

Thanks RonD! It's the turn signal flasher relay that is 'clicking'. The flashing stops when I remove it, and of course the lights go out too. Your diagram shows a couple extra grounds that no other diagrams I've seen had - G100 and G104. I've even had difficulty finding a fuse box diagram showing the correct placement of fuses!
I'm going to see if I can find a picture diagram showing where the location on the rear chassis these two grounds are located. Thing is, according to the diagram, it should be affecting the brake lights too but that doesn't seem to be the case here. I'm wondering if it could be a bad connection with the back up lights. Your diagram shows the PPL/O wire going to the power distribution from the turn signal flasher, while the diagram I have shows the lead going to the back up lights.
Since both rear lights are flashing simultaneously through the turn signal flasher and not affecting the front signal lights and both wires connecting the rear signal lights go directly from the multi-function switch to the rear lights uninterrupted, it's got to either be a bad multi-function switch or a bad ground.

 

I can't see it being a bad Ground since the lights flash without turn signal lever selecting either side.
A bad ground on one light will cause current to flow to another light with a good ground causing both to light up.

If both were flashing when only 1 was selected then yes bad ground could be the issue.

Your turn flasher is "seeing" a load from the rear lights with key on so best guess would be problem in multi-function switch or shorted wires at that switch.

So light blue wire from flasher to switch, and light green and orange wires from switch to lights are connected when switch is in Neutral position.

On later model rangers the Brake and turn bulbs were the same, so using multi-function switch for those models could cause your issue, so make sure you got a multi-function switch for dual bulb setup

 

Hey RonD!
Thanks for all your help! It was a bad multi-function switch. There's a junk yard nearby so I went and found a '94 Ranger - they had around 20 or 30 ranging from 1989 - 2011 so I had my pick. I grabbed one that looked in the best condition considering the fact it's in a junk yard, and plugged it up and everything worked like it should!
Appreciate your help!

 

Good work

Thanks for posting an update and what fixed it, should help others down the road