How are rear blinkers supposed to perform? (1989 2.9L automatic)

[eightynine4x4]

I’ve finally noticed this by parking the vehicle and testing at night. When the lights are on, there is no rear blinker activity. The lights simply remain illuminated.
I was imagining they’d grow brighter during blinks, I guess? How is it supposed to appear? Or is there simply no rear blinker action when lights are on?
Also, how do rear blinkers illumination relate to brake lights?
There are two bulbs in back. One is behind clear plastic and is for reverse. The other is behind red plastic so obviously indicates for brakes, lights ON, and turn signals. Do I have a grounding issue or something?

 

[RonD]

1989 don't have separate turn signal lights in the rear, brake/turn share half(1 filament) of a Dual filament light bulb
1990 to 1999 had separate turn bulbs in the rear, just FYI
2000 and up went back to sharing

Anyway in 1989 the brake switch sends 12volts to the turn signal stalk(multi-function switch), when brake pedal is pressed
If turn signals are off then that 12volts goes out to BOTH left and right wires and both brake lights come on

If you turn on left turn signal then the left wire is connected to Flasher and brake light wire is disconnected on Left side, but would still work on right side, and visa versa

IF.........both rear brake lights work then both left and right wires that run from multi-function switch to the 2 bulbs work and the bulbs are good

Brake/turn filament is twice as bright as Park light filament, so quite easy to tell if they are working

If turn signals are not working in the rear but are in the front and on the dash, then most likely issue is IN the multi-function switch
The front and dash turn lights are on a separate switch inside the multi-function switch, because they don't share a wire with brake lights

The Park lights use the other filament in the dual filament bulb, and have no connection to brake or turn light system, their 12v comes from main light switch


Wiring diagram here: https://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

 

[Curious Hound]

RonD's answer is technically better.

I just wanted to reply with;

"On, off, on, off, on, off, on, off, on, off, on, off, on, off..."

 

[Ranger850]

You might also want to check to see if you have the correct bulb. There should be TWO filaments in the bulb, one for brake and one for blink.

 

[eightynine4x4]

RonD's answer is technically better.

I just wanted to reply with;

"On, off, on, off, on, off, on, off, on, off, on, off, on, off..."

that works!

You might also want to check to see if you have the correct bulb. There should be TWO filaments in the bulb, one for brake and one for blink.

Yes, i just realized that. I shopped for new bulbs locally last week and got the right specs but hadn't realized i needed to be looking for dual filament.


Reading Ron's more scholastic description made me realize something very stupid i hadn't thought of.... Do I have to test the rear blinkers while driving? If i'm parked and i have the truck's "lights on", and the rear lights are constantly illuminated, and then i hit the turn signal.... i suppose the turn signal only functions when i'm no longer in park? And for functional reference.. when i have the truck's lights off, and i'm parked and doing this test, the rear blinkers work fine.

 

[Ranger850]

that works!



Yes, i just realized that. I shopped for new bulbs locally last week and got the right specs but hadn't realized i needed to be looking for dual filament.


Reading Ron's more scholastic description made me realize something very stupid i hadn't thought of.... Do I have to test the rear blinkers while driving? If i'm parked and i have the truck's "lights on", and the rear lights are constantly illuminated, and then i hit the turn signal.... i suppose the turn signal only functions when i'm no longer in park? And for functional reference.. when i have the truck's lights off, and i'm parked and doing this test, the rear blinkers work fine.

My 87 Nissan truck has to have "key ON" for the blinkers to work. If I have lights on/Key off, No blink. Key on/ Lights on OR off, blink.

 

[Curious Hound]

Should work whether driving or not and with or without other lights on. You should be able to put key in, turn it on and turn blinkers on and they should work. If headlights are on, then with blinker on it should look like the light gets brighter, dimmer, brighter, dimmer, etc.

 

[eightynine4x4]

My 87 Nissan truck has to have "key ON" for the blinkers to work. If I have lights on/Key off, No blink. Key on/ Lights on OR off, blink.

Should work whether driving or not and with or without other lights on.

Hmmmmmmmmm now I have to finish my nice hot coffee and get out there in the cold cold world

 

[fastpakr]

RonD's answer is technically better.

I just wanted to reply with;

"On, off, on, off, on, off, on, off, on, off, on, off, on, off..."

I was -really- close to replying 'intermittently'.

 

[Curious Hound]

now I have to finish my nice hot coffee and get out there in the cold cold world

I know that feeling. I'm waiting to go out and refill the differential on my Fun50. Just not ready to crawl under there in the cold yet.

 

[dvdswan]

My 87 Nissan truck has to have "key ON" for the blinkers to work. If I have lights on/Key off, No blink. Key on/ Lights on OR off, blink.

You also have a separate blinker light on the Nissan.

 

[Ranger850]

You also have a separate blinker light on the Nissan.
View attachment 68609

I know. But the KEY has to be ON for them to work.

 

[pjtoledo]

friendly FYI
the 4 way flashers activate the brake lights. that way you can turn the flashers on ( ) and do a walk around to check front & rear bulbs.

 

[eightynine4x4]

friendly FYI
the 4 way flashers activate the brake lights. that way you can turn the flashers on ( ) and do a walk around to check front & rear bulbs.

Nice!! Yeah I'll do that too thanks! I will be checking all these things shortly here... I'm hoping it's the filament issue since that's a 6$ and 10 minute repair job.

 

[eightynine4x4]

1989 don't have separate turn signal lights in the rear, brake/turn share half(1 filament) of a Dual filament light bulb
1990 to 1999 had separate turn bulbs in the rear, just FYI
2000 and up went back to sharing

Anyway in 1989 the brake switch sends 12volts to the turn signal stalk(multi-function switch), when brake pedal is pressed
If turn signals are off then that 12volts goes out to BOTH left and right wires and both brake lights come on

If you turn on left turn signal then the left wire is connected to Flasher and brake light wire is disconnected on Left side, but would still work on right side, and visa versa

IF.........both rear brake lights work then both left and right wires that run from multi-function switch to the 2 bulbs work and the bulbs are good

Brake/turn filament is twice as bright as Park light filament, so quite easy to tell if they are working

If turn signals are not working in the rear but are in the front and on the dash, then most likely issue is IN the multi-function switch
The front and dash turn lights are on a separate switch inside the multi-function switch, because they don't share a wire with brake lights

The Park lights use the other filament in the dual filament bulb, and have no connection to brake or turn light system, their 12v comes from main light switch


Wiring diagram here: https://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

The verdict is in! And it's a weird one...
The bulbs are in fact dual filament.
And, all of my circuitry works.
But get this... the bulbs are designed weirdly, in two ways. Probably just need to order proper bulbs that are somehow in someway approved by Ford, err something.

1, the turn-lock design in the bulb housings is clearly expecting the bulbs to be inserted into the grooves and then turned clockwise like 15-20 degrees to lock in place. But, with these bulbs, that breaks the connection to one of the filaments. It's clear as day.. if i insert the bulb fully in, and that's it, the whole system works. But that isn't secure, it could wobble out over time. It's not loose, but there's nothing keeping it from wobbling gradually out. And when you look at the two metal "prongs" on the bulb and compare them to the socket prongs, sure enough they line up perfectly, so long as you don't twist lock the bulb. Once you twist lock them, one of the filaments is disconnected. The other still has enough contact to work. In my case, it's the park/on circuit that remains functional.

2, the brighter stronger filament is aligned to the park/on circuit, and the dimmer smaller filament is aligned to the turn/brake circuit. There is no mistaking this on my part, because you can only insert the bulb one way due to the notches being designed for just that. So it's backwards as per what Ron is saying, that the brake/turn filament should be brighter.

I guess the issue could be the sockets themselves but that doesn't sound very probable.

A workaround is that i can simply cut and flip the wiring to the sockets, and then maybe put some electrical tape around the base of the bulb to help keep it from slowly coming out. That would probably work fine.

I had picked these up from auto zone and they matched all electronic specs and physical attributes compared to what was marked on the old bulbs. But clearly I hadn't noticed the filament flip flop nor the twist lock alignment in relation to the prongs! Who'd a thunk.

I'll try shopping around for something certified but maybe i should just do the workaround and live with it instead of just spending more money.