No turn signals or hazard lights, fuse intact. (2 Viewers)

[Jonathan Hanson]

Some time ago the "turn/gen" fuse (turn signals and voltage regulator) on my '73 FJ40 began blowing randomly. Since I hadn't replaced either the alternator or the voltage regulator in at least 20 years, I decided to do so as a precaution and to see if that fixed the issue. It didn't. The fuse kept blowing, cutting out both turn signals/emergency flashers and the alternator. Just a few days ago, the signals and flashers again stopped working . . . but this time the fuse hasn't blown; the voltage regulator is still getting power. I'm stumped. I took apart the turn signal assembly and all seems fine inside. I have a solid-state flasher, so I hooked up the factory unit again—still nothing. I don't know where to look to see where the power to the signals has been lost.

 

[Cruiserman13]

Some time ago the "turn/gen" fuse (turn signals and voltage regulator) on my '73 FJ40 began blowing randomly. Since I hadn't replaced either the alternator or the voltage regulator in at least 20 years, I decided to do so as a precaution and to see if that fixed the issue. It didn't. The fuse kept blowing, cutting out both turn signals/emergency flashers and the alternator. Just a few days ago, the signals and flashers again stopped working . . . but this time the fuse hasn't blown; the voltage regulator is still getting power. I'm stumped. I took apart the turn signal assembly and all seems fine inside. I have a solid-state flasher, so I hooked up the factory unit again—still nothing. I don't know where to look to see where the power to the signals has been lost.

I had similar issues with my 73 and ended up disassembling and cleaning up the hazard switch assembly and the problem was fixed.

 

[Jonathan Hanson]

I had similar issues with my 73 and ended up disassembling and cleaning up the hazard switch assembly and the problem was fixed.

Okay, I'll give that a try. Thanks very much.

 

[45Dougal]

Sounds like the hazard switch or switch connector. Blast it with some contact cleaner and click it on and out 20 times.
The connector could expecially be suffering from water ingress down there

 

[hobbes]

If the rear lights are also totally dead (brake, running lights) make sure the connector they share is securely attached to the rear of the fuse box. This connector also affects the interior light and cigarette lighter (which are easier to check).

 

[Jonathan Hanson]

Thanks for the input. The running lights are fine. I disassembled and cleaned the hazard switch (below): no difference. I'm still stumped.

 

[45Dougal]

Which wiring diagram are you using?

On my diagram the turn signal does not share a fuse with the regulator.

The turn signal uses the turn fuse (key set to ign), and the Hazards use the stop fuse (key any /off).

You should have 12v at both green-red wires at the hazard connector (this shows that both fuses and connections are sound).

If you do, then check if you have 12v at the green-white wire at the flasher.

If this is all working then the problem is downstream.
Remove the flasher unit and try testing the resistance between the green- blue wire to ground.
This should read a few ohms when the hazard switch is On, and about half this when the indicator switch is on.

 

[ToyotaMatt]

Thanks for the input. The running lights are fine. I disassembled and cleaned the hazard switch (below): no difference. I'm still stumped.

View attachment 3333782

- lets see inside each end of this HAZARD switch , its 2 mating conenectors ?

- this switch uses a WAFFLE siamese connector set up they arfe natorious for having issues




.3

-

 

[Jonathan Hanson]

I'm using a factory diagram. The turn signals and voltage regulator definitely share a fuse:

The connector to the hazard switch looked to be in good shape. Testing power to the hazard switch, I got power on always to the green/red wire, power with ignition on also to the green/orange wire, and power with the brake on to the green/yellow wire. Given that and the cleaning I did, I don't *think* the issue is with the hazard switch. I also tried three different flashers—the factory one and two new solid-state flashers—so I don't think that's the issue either. Still a mystery why the turn signal fuse is intact and I have power to the voltage regulator, but no signals or hazards!

 

[Jonathan Hanson]

There is no power to any of the turn signal contacts with the ignition on. But there's power at the fuse. I think that leads me back to the hazard switch, but I can't figure out which contacts at the hazard switch connector to jump to find out. The switch seems fine after cleaning, and the contacts looked fine too.

 

[45Dougal]

There is no power to any of the turn signal contacts with the ignition on. But there's power at the fuse. I think that leads me back to the hazard switch, but I can't figure out which contacts at the hazard switch connector to jump to find out. The switch seems fine after cleaning, and the contacts looked fine too.View attachment 3334237

Ah sorry my bad - I read 78 in place of 73.

Maybe this diagram from the later manual is helpful? Basically the same setup but the green-orange is green-black everywhere.

 

[45Dougal]

I'd try and measure resistance between each Green-black to ground and then each green-yellow to ground.

You should measure the resistance of the bulbs (assuming they're not LED, this resistance enables the flasher unit to work).

If you flash power onto either of these 4 wires at the hazard switch, you should light up one corner.

 

[Jonathan Hanson]

I might have found it. The upper left connection here—which is ignition-excited and connected through the hazard switch to the turn signal assembly, I think—looks decidedly dodgy.

 

[Jonathan Hanson]

Ah sorry my bad - I read 78 in place of 73.

Maybe this diagram from the later manual is helpful? Basically the same setup but the green-orange is green-black everywhere.

View attachment 3334278

That is helpful, thanks!

 

[Jonathan Hanson]

And . . . solved. It was that single contact, which had clearly been going bad and blowing the fuse before it lost contact altogether. I wired in a jump around the plug for that circuit for now, and everything came up again—turn signals and hazard flashers. Thank you for all the valuable input!

 

[ToyotaMatt]

And . . . solved. It was that single contact, which had clearly been going bad and blowing the fuse before it lost contact altogether. I wired in a jump around the plug for that circuit for now, and everything came up again—turn signals and hazard flashers. Thank you for all the valuable input!

this is ONLY a band-aid get you home safe one way type repair , and does not address the root causes , nor prevents this from happening again .......fyi


matt

 

[45Dougal]

And . . . solved. It was that single contact, which had clearly been going bad and blowing the fuse before it lost contact altogether. I wired in a jump around the plug for that circuit for now, and everything came up again—turn signals and hazard flashers. Thank you for all the valuable input!

Glad to hear it's all working!

The turn signals should be on a different fuse to the Hazards, so I'm curious is there is another dirty contact or another problem elsewhere.

I guess your turn signal now works without the ignition (or else your hazards only work with the ignition switched on)?

A good clean with some fine sand paper and some vaseline should fix it anyway.

 

[Jonathan Hanson]

this is ONLY a band-aid get you home safe one way type repair , and does not address the root causes , nor prevents this from happening again .......fyi


matt

That's why I wrote, "for now . . ."

 

[Jonathan Hanson]

Glad to hear it's all working!

The turn signals should be on a different fuse to the Hazards, so I'm curious is there is another dirty contact or another problem elsewhere.

I guess your turn signal now works without the ignition (or else your hazards only work with the ignition switched on)?

A good clean with some fine sand paper and some vaseline should fix it anyway.

That's a good point. Hazards work with ignition off. Since I cleaned all the contacts in the hazard switch, and cleaned and applied dialectric grease to the connector, perhaps I solved two issues at once? I'm still vague on all the functions that run through the hazard switch; it was a real education.

 

[ToyotaMatt]

That's why I wrote, "for now . . ."

sorry , i did miss the ' for now "