Need help with turn signal wiring - 72/73 FJ40

[woytovich]

Note that the hazards work but the turn signals do not (no light, no flash, no relay click-click), fuses are all good, flasher & turns work when flasher is directly powered.
We have determined that there is no (ignition switched) power getting to the flasher.
I would LIKE to understand where that power to the flasher comes from after it leaves the ignition switch so I can try to track down the failure point.
Failing that I'll power the flasher with some other available ignition switched power.

 

[coondawg]

Power to flasher on ‘72 (12/71) comes from hazard switch.

 

[coondawg]

Green/White wire from hazard switch goes to flasher power. The load (Green/Blue) returns to hazard switch. Turn signals can get a little confusing. Green wire from hazard switch goes to power terminal of turn signal switch. GY wires go to right turn signals, Haines diagram shows Green/Black going to Green/Orange (left turn signals) at the turn signal switch, but I’m pretty sure mine are Green/Orange all the way. Note that the hazards work via the turn signal switch, so if hazards are working, there’s better than even odds to you have dirty or corroded terminals inside the turn signal switch.

 

[woytovich]

so if hazards are working, there’s better than even odds to you have dirty or corroded terminals inside the turn signal switch.

Thanks for the info. Given that the hazards work AND the turns work when +12 is applied to the flasher relay WHERE in the turn signal switch is power conveyed to the flasher relay? (If I'm understanding)
Or maybe you can draw up a diagram...?

 

[charliemeyer007]

I had to rebuild the switch box down by the floor way back in 85 or so. There are big copper contact that were arc very badly, plus a lot of the phenolic plastic was burnt away. I filled it with epoxy and bent the sliding contacts after cleaning them so it made good contact.

 

[woytovich]

switch box down by the floor

What box are you referring to?

 

[woytovich]

Green/White wire from hazard switch goes to flasher power. The load (Green/Blue) returns to hazard switch. Turn signals can get a little confusing. Green wire from hazard switch goes to power terminal of turn signal switch. GY wires go to right turn signals, Haines diagram shows Green/Black going to Green/Orange (left turn signals) at the turn signal switch, but I’m pretty sure mine are Green/Orange all the way. Note that the hazards work via the turn signal switch, so if hazards are working, there’s better than even odds to you have dirty or corroded terminals inside the turn signal switch.

How's this: (Green/Blue, Green/White and Green)

 

[charliemeyer007]

On mine there is a rod going down next to the steering column from the the turn signal lever to the box near the pedals. Its been a while since I rebuilt the box.

 

[woytovich]

Here is an updated diagram showing where the power to the hazard switch comes from
(ammeter > alternator > regulator > hazard switch).

 

[woytovich]

Temporary fix in place - the owner will dig in and repair this properly when they get back to the truck). Jumped ignition hot from the back of the fuse block to the flasher (while retaining the needed connections for the hazards, thus the loop) A little janky but once I buttoned it all up everything is safe and stable.
(PSA: yes, I know I should have considered using different color wire... my bad)

 

[raymond2335]

Temporary fix in place - the owner will dig in and repair this properly when they get back to the truck). Jumped ignition hot from the back of the fuse block to the flasher (while retaining the needed connections for the hazards, thus the loop) A little janky but once I buttoned it all up everything is safe and stable.
(PSA: yes, I know I should have considered using different color wire... my bad)



View attachment 4024882

View attachment 4024883

 

[coondawg]

Mark,

Sorry, I’ve been out-of-pocket for a few days.

Just to confirm your diagram (for the most part). The Hazard switch terminals are as follows:

B1 = Power in from alternator via Fuse #7 when key is on. Required for turn signals.
(NOTE: The voltage regulator doesn’t come into play here. This regulator also *gets*
power from Fuse #7 and feeds it to the alternator. It was built in to the alternator
itself in later years and now the vehicle’s ECU does this work.
B2 = Power in from battery via Fuse #2. Always hot so (just the)hazards work when ignition is on
L1 = Flasher Load — on/off when there is a load (hazards on or turn signal on)
F = Flasher Power — always hot, either via B1 or B2
L3 = Front left turn signal and indicator bulb
L6 = Power to turn signal switch — always hot from L1 (flasher load). Moving switch to left or right
adds load and lights flash
L2 = Front right turn signal and indicator bulb
L4 = Right rear turn signal
L5 = Left rear turn signal

Turn signal switch terminals are:

S = Stop (Brake) Lights — Power in from Stop Light switch — right rear jumpered to left rear
RR = Rear right light
FR = Front right light
B: Power in from L6 on Hazard switch
FL = Front left light
RL = Rear left light

Since you state adding +12 to flasher gives you both signals and hazards, I believe your hazard switch perhaps was/is only connected to battery power on B2. B2 only powers the hazards. No power goes to the turn signal switch That’s why your temp fix is working.

 

[woytovich]

Wow, that's a lot of info. I would have to sit down and revisit my diagram and spin up some brain power. Maybe someone with more 12-volt electrical experience and knowledge can chime in here. I would love to take what you've written and further understand what's happening.

 

[coondawg]

Wow, that's a lot of info. I would have to sit down and revisit my diagram and spin up some brain power. Maybe someone with more 12-volt electrical experience and knowledge can chime in here. I would love to take what you've written and further understand what's happening.

I don’t blame you! This setup was definitely designed by an engineer, not a maintainer and it's not easy to figure out. Here’s about as easy an explanation as you can get.

1. Hazard Switch is brains of the operation
2. Ignition off/hazard on
— battery power goes from hazard switch to flasher and back again
— hazards work, turn signals don’t work
3. Ignition on/hazard off
— Power goes via ignition switch to hazard switch to flasher and back again
— Hazard switch also directs power to turn signal switch (even when off)
— hazards work, turn signals work
4. Brake pedal depressed (other switch positions don’t matter)
— Power sent from brake light switch to tail light via turn signal switch
— independent of flasher and hazards so you always get steady brake lights

If you’re just looking for different words, you can have a look at Coolerman’s explanation here Hazard/TurnSignal Operation - https://globalsoftware-inc.com/coolerman/fj40/6A.htm

He’s explaining his own ‘71, but it’s the same principle.