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Why do both rear turn signals blink when the right side is turned on?


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On my 90 ford ranger, both rear turn signals will blink when the right side is turned on, while the right front blinker blinks ok..

The front and back blinkers work fine when the left side blinker is turned on?

I don't know what's causing both rear turn signals to flash when I use the right blinker, as the left side works fine without any problems..

Another thing I noticed is that if I put on the right side blinker, without the key in the ignition, and press the brake pedal..

The right front, driver's side, turn signal light will light up and the turn signal flasher will start clicking, but the right front turn signal doesn't flash, while the brake pedal is being depressed and the rear brake lights will stay on..

While the turn signal flasher is clicking, as explained.. When I turn the heater blower motor's switch on, without the key on.. Each time the turn signal flasher clicks, the heater blower motor will start up on each click the flasher makes and then stop between each click..

Another thing I also noticed is if I put on the emergency flashers they will work fine, until I depress the brake pedal..

Then the emergecncy flasher lights will stay on and stop flashing, as long as the brake pedal is depressed..

I've never had a problem like this, before..

What is the solution to this problem, when the right side blinker is turned on and both rear blinkers will start blinking?

Do you think the turn signal switch is faulty and is somehow crossing power over to the rear left side blinker, when the right side blinker is turned on?

Has anyone else experienced this kind of problem, before, and know what needs to be done to fix it?
 
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Andy D

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I'm guessing the right blinker is "looking" for a better ground
 

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if both lights blink in unison and are both bright, i would suspect the turn signal switch. it may be shorting in the brake light circuit, as it runs through the turn signal switch, but only for the rear. i have had the same problem before, turned out to be metal shavings from the horn contact stuck in the grease in the turn signal switch! that was from a car built in the late 60's, not sure if there is dielectric grease in the newer switches. hope this helps
 
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I'm guessing the right blinker is "looking" for a better ground
If you're guessing the right rear turn signal blinker is "looking" for a better ground, as you mentioned..

Could that cause the left rear turn signal blinker to blink, while the right rear turn signal is blinking?
 
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if both lights blink in unison and are both bright, i would suspect the turn signal switch. it may be shorting in the brake light circuit, as it runs through the turn signal switch, but only for the rear. i have had the same problem before, turned out to be metal shavings from the horn contact stuck in the grease in the turn signal switch! that was from a car built in the late 60's, not sure if there is dielectric grease in the newer switches. hope this helps
How long did it take you to figure that one out, before you found the cause of your problem?

When it comes to mechanics, sometimes, you never know what you will run into, when you start trouble shooting the possible causes of a problem..

Until I find out for sure, I'm thinking my problem is probably in my turn signal switch, too, for causing the current some how to cross over to the left rear side, from the right rear side, which could be making both my ranger's rear turn signals to blink, at the same time..

What year turn signals switch's fit a 1990 ranger, and does anyone have a spare one for cheap..
 
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I'm guessing the right blinker is "looking" for a better ground
Where are the 90 Ranger tail light blinker grounds located, if you'e guessing the right blinker is "looking" for a better ground..
 
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if both lights blink in unison and are both bright, i would suspect the turn signal switch. it may be shorting in the brake light circuit, as it runs through the turn signal switch, but only for the rear. i have had the same problem before, turned out to be metal shavings from the horn contact stuck in the grease in the turn signal switch! that was from a car built in the late 60's, not sure if there is dielectric grease in the newer switches. hope this helps
I took the turn signal switch apart and cleaned all the contacts inside..

It's still doing the same thing, when I turn on the right turn signal switch, both rear tail light turn signals blink, at the same time, nice and bright..

Do you think something is worn inside the turn signal switch, that is causing this problem and somehow causing the current to cross over to both rear tail light turn signal bulbs, which is making them both to blink, at the same time, when the right turn signal switch is used..
 

shane96ranger

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Where are the 90 Ranger tail light blinker grounds located
This really doesn't matter. If you suspect bad ground is the issue, make a new ground for each side. My trailer that was an 87 bed had a bad ground, and I grounded them right behind the tail light.
 
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This really doesn't matter. If you suspect bad ground is the issue, make a new ground for each side. My trailer that was an 87 bed had a bad ground, and I grounded them right behind the tail light.
Was your bad ground causing both your rear turn signals to blink nice and bright, at the same time, when using the right turn signal switch?

I'm trying to find the solution to the source of the problem..

If I had a bad ground, both my Ranger's tail light blinkers, even though they're, for some reason blinking nice and bright, at the same time, when the right turn signal switch is on, wouldn't be the symptom of having a bad ground, would it?

If there was a bad ground for the tail light turn signals, somewhere..

Wouldn't a turn signal that had a bad ground, either cause it to not work at all, or else be dimly lit, or else cause it to maybe work intermittingly..
 

shane96ranger

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Yes mine made both sides flash in my Explorer as well. It is extremely easy to see if a ground is a fix. You could have checked it in the same time it took to type why you think it's not a ground issue.

Three things off the top if my head to check. Ground, the bulb sockets, and then the switch.

Sent while I should be doing something else
 
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Yes mine made both sides flash in my Explorer as well. It is extremely easy to see if a ground is a fix. You could have checked it in the same time it took to type why you think it's not a ground issue.

Three things off the top if my head to check. Ground, the bulb sockets, and then the switch.

Sent while I should be doing something else
When I used a continuity test light on the left and right tail light turn signal's sockets for connecting it to the turn signal's socket inside ground, with the bulb removed, and placed the conintuity test light's probe on the turn signal's inside socket's 12 volt power contact connection for the bulb..

It would light up the continuity test light on both the left and right side, while I tested the turn signal sockets for getting a ground and power..

Assuming I did this correctly and this is a valid test procedure..

The only other alternative would be a defective turn signal switch, which would be causing this problem, as explained, wouldn't it?
 

shane96ranger

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When I used a continuity test light on the left and right tail light turn signal's sockets for connecting it to the turn signal's socket inside ground, with the bulb removed, and placed the conintuity test light's probe on the turn signal's inside socket's 12 volt power contact connection for the bulb..

It would light up the continuity test light on both the left and right side, while I tested the turn signal sockets for getting a ground and power..

Assuming I did this correctly and this is a valid test procedure..

The only other alternative would be a defective turn signal switch, which would be causing this problem, as explained, wouldn't it?
If you took the turn signal apart, it should have been fairly easy to see if that was the problem - at least it was from my experience cleaning out a switch (PO dumped a coke or something on the steering column). My experience is taking the switch apart in my F150. I would think yours should be very similar. Have you tried playing with or replacing the flasher relay?
 
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If you took the turn signal apart, it should have been fairly easy to see if that was the problem - at least it was from my experience cleaning out a switch (PO dumped a coke or something on the steering column). My experience is taking the switch apart in my F150. I would think yours should be very similar. Have you tried playing with or replacing the flasher relay?
When I took the turn signal switch apart and cleaned out the oxidation inside..

I thought that might solve my problem, but it didn't..

I didn't see anything, noticably wrong with the turn signal switch on the inside..

However, the turn signal lever seems kind of sloppy from wear, that goes into the turn signal switch..

Maybe, the sloppy turn signal lever could be causing a problem inside the turn signal switch, itself, if it's not properly aligning up all the different components inside the turn signal switch, as needed, for performing it's different functions..
 

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Filament in one of the bulbs has broken and fallen onto the other filament. This makes the blinking cross over to the other side via the parking light circuit.

Either replace the front turn signal/parking light bulbs and the rear turn/brake/parking bulbs or remove and inspect them all till you find the bad one.

Bad ground do cause weird things to happen, verify all grounds.

Charles
 
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Filament in one of the bulbs has broken and fallen onto the other filament. This makes the blinking cross over to the other side via the parking light circuit.

Either replace the front turn signal/parking light bulbs and the rear turn/brake/parking bulbs or remove and inspect them all till you find the bad one.

Bad ground do cause weird things to happen, verify all grounds.

Charles
Nothing I've done, so far, has stopped both rear turn signals from flashing when I use the right turn signal..

I tried replacing the front and rear bulbs..

I tried a different turn signal flasher..

I tried a different emergency signal flasher..

I took the turn signal switch apart and cleaned it..

I tried my other 89 Ranger's turn signal switch..

I've cleaned all the ground connections that I could find..

Every electrical connector that's under the the hood I've taken apart cleaned and sprayed with WD/40..

I took the brake light switch off and sprayed it with WD/40..

I don't know what's causing both rear turn signals to flash when I use the right blinker, as the left side works fine without any problems..

Another thing I noticed is that if I put on the right side blinker, without the key in the ignition, and press the brake pedal..

The right front, driver's side, turn signal light will come on and the turn signal flasher will start clicking, but the right front turn signal won't flash, while the brake pedal is depressed and the brake lights are on..

Another thing I also noticed is if I put on the emergency flashers they will work fine, until I depress the brake pedal..

Then the emergecncy flasher lights will stay on and stop flashing, as long as the brake pedal is depressed..

I've never had a problem like this, before..

If anyone else has had a problem like this, before, what did you find was causing it..
 
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