FJ40 Turn Signal Trouble shooting (1 Viewer)

[Goforth]

Just to refresh: Key must be on to get the turn signals to work.
You should have +12V on the Green/Red wire in that two pin connector when the key is on. The Green/Blue (or Green/White) wire goes from the connector to the turn switch. If you do not have power on the GR wire when the key is on, then check the fuse, fuse clips and connections to the fuse panel.

I'm in process of checking cables. I'm starting at the battery and through the starter. All fuses in the fuse panel are good. Just starting to trace it all out. Finding some really weird behavior too. I am losing ALL power at times as I wiggle the wires while tracing them. I experience parking lights that will work but headlights won't come one. Feel like I'm going backwards in progress!

When I press the brake, the rear lights illuminate as they should. When I can take it a step further and use the turn indicator, it will turn off the brake light for whichever direction I have the indicator. Does this make sense or is this behavior odd?

Thanks
charles

 

[Coolerman]

That is normal behavior for the brake/turn using a single element in the bulb. Brake takes priority. When you turn on the turn signal it is actually just flashing the brake light.

If you are losing all power at times check the connection of the large WHITE wire to the starter B+ stud and also the amp meter connections on the back of the gauge cluster. PLEASE make sure you disconnect the battery cable before removing the gauge cluster! You can fry the entire harness if you don't heed that advice!

FYI I make a fusible link that attaches to the Starter B+ stud that helps protect against that issue.

 

[Goforth]

That is normal behavior for the brake/turn using a single element in the bulb. Brake takes priority. When you turn on the turn signal it is actually just flashing the brake light.

If you are losing all power at times check the connection of the large WHITE wire to the starter B+ stud and also the amp meter connections on the back of the gauge cluster. PLEASE make sure you disconnect the battery cable before removing the gauge cluster! You can fry the entire harness if you don't heed that advice!

FYI I make a fusible link that attaches to the Starter B+ stud that helps protect against that issue.

I'll take you up on the fusible link. I think I'm also in line for a harness for my '67! Most work done without the battery connected. I'll take a look at the amp meter connection on the cluster next.

Thanks!
charles

 

[Goforth]

Another odd behavior I am experiencing, when I turn on the headlights occasionally I lose power. Not sure if this would incriminate the voltage regulator. I'll get power back but not always will the headlights work immediately. Clearly something funky.

 

[Goforth]

Pulled the instrument cluster loose the cables to the amp meter sure look suspicious:

 

[Coolerman]

Uh yeah, I would say you have found your issue! Hopefully that melting is only right there at the connections and not all through the white and white/blue wires? Looks like it may have shorted right at the amp meter connections. Take those connections loose, clean them and the post, n tape it up good, and try it again.
I also sell those amp meter ring terminals for the white and white/blue wires. You can cut off the bad wire and crimp/solder on the new terminals. You should have plenty of slack to do it. Send your address to fj40coolerman at gmail dot com and I will get you a total for the link and anything else you might need. I will build the link tonight.

 

[rghouse]

I had the same issue on the 79'. The hazards worked, but the passenger side signals did not.

Electrical guy in town came by and diagnosed the turn signal switch (unit in the column connected to arm you use when driving- for those that don't know) in 5 minutes. He actually jostled the arm around a bunch (I cringed a bit, thinking it would snap off) and now it works fine. He recommended replacing it of course but I'm running with it for now. Thanks to all for input here guys

 

[12112321AKYLE]

Having the same issue as the one who started this thread with my '76 FJ40.. all lights work except turn signals. I tested a few things already, including the "GL" wire that is mentioned in a service manual I have.

If this wire pictured is the GL wire (green-light purple), i get around 8 volts with the turn signal switch in the resting/off position and 0 volts when I turn the switch one way or another. Does this rule out that the turn signal switch is bad?

 

[45Dougal]

As you see in the wiring diagram, the hazard lights are powered through the stop fuse, while the indicators (turn signals) are powered from the turn fuse.
Both run through the hazard switch connector.
Check the hazard switch connector isn't corroded or loose.
Check the turn fuse is sending power to that connector (when ignition is switched on).
The GL wire is actually two wires which join through that same connector. Check for continuity between them.

 

[ToyotaMatt]

Having the same issue as the one who started this thread with my '76 FJ40.. all lights work except turn signals. I tested a few things already, including the "GL" wire that is mentioned in a service manual I have.

If this wire pictured is the GL wire (green-light purple), i get around 8 volts with the turn signal switch in the resting/off position and 0 volts when I turn the switch one way or another. Does this rule out that the turn signal switch is bad?

View attachment 3310893

View attachment 3310894

Having the same issue as the one who started this thread with my '76 FJ40.. all lights work except turn signals. I tested a few things already, including the "GL" wire that is mentioned in a service manual I have.

If this wire pictured is the GL wire (green-light purple), i get around 8 volts with the turn signal switch in the resting/off position and 0 volts when I turn the switch one way or another. Does this rule out that the turn signal switch is bad?

View attachment 3310893

View attachment 3310894

As you see in the wiring diagram, the hazard lights are powered through the stop fuse, while the indicators (turn signals) are powered from the turn fuse.
Both run through the hazard switch connector.
Check the hazard switch connector isn't corroded or loose.
Check the turn fuse is sending power to that connector (when ignition is switched on).
The GL wire is actually two wires which join through that same connector. Check for continuity between them.

- here is a 3rd GEN. and 4th GEN. HAZARD SWITCH details Spec.

- a BAD CONNECTOR Housing / Housings / TERMINALS does cause the above symptoms

- so can the switch itself internally absolutely does burn up from age time corrosion ....

- the TURN SIGNAL switch CAN be involved here , but typically does NOT short circuit up top at the horn contact , BUT the LOWER two connectors CAN burn up in every way ...

- so Careful inspection of the 4pin and 2pin connector plugs is absolutely necessary here 100%

- the FLASHER BOX or CAN 81980- i have NOT seen burn up ever ? the do fail inside but do NOT cause any other bad electrical problems




- i offer both NOS and professionally Restored inside and out HAZARD switches 's

- all post restore bench tested of course.....


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[ToyotaMatt]

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9/73 - 9/77

SWITCH SUB ASSY.
HAZARD

WARNING SIGNAL
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[MatthewMcD]

I am experiencing the "Hazards work but turn signals only blink once then stop" issue. The rear marker lights were a rusty mess. I have ordered new ones but am wondering if, while the rear marker lights are removed from the system, can I continue my troubleshooting or do I need them to make the system work? I would think it should work, but reading the threads it sounds like the system is sensitive to the lack of current draw and it might be better to wait. (I have to troubleshoot the backup lights, so I have plenty to do in the mean time.)

 

[pb4ugo]

All the turn signals need to be connected and working and be the correct wattage. The mecahical flasher needs the amp draw to activate.

 

[45Dougal]

If you're desperate to test it, you can fit 21w in all four front bulbs to make it work, but may as well just wait.

 

[MatthewMcD]

I installed my replacement marker lights and (since they don't blink) haven't changed the blinker behavior. The blinkers still turn on once and stay on. Reviewing other threads, while I am rechecking grounds on the 4 indicator lights in the circuit (two on each side in the '75), I am going to check the wattage of the installed bulbs.

I have only found specs for replacement LEDs in the threads. I looked in the FSM and didn't find it.

Haynes lists them as 21W is this correct?

EDIT: OK, I just found this and read it more carefully, Light bulbs for Land Cruisers - https://forum.ih8mud.com/threads/light-bulbs-for-land-cruisers.69423/ lists the original bulbs. #1156 are rated at 26.9W

 

[MatthewMcD]

Here's one last bit of info. While checking the grounds I noticed one possible issue, but I need clarification. Correct me if I am wrong:

1. On the front light assembly, the side marker is the turn signal. Should only be on when turn signal is selected.
2. The top front is "parking light" on when the headlights are on.
3. Bottom front is turn signal and on when turn signal is selected.

Is that correct? Because this is what I am currently seeing when the signals are "frozen" with right blinker on. Looks like the wiring is wrong.

The grounds are good, there is continuity through the bezel of the lights to the chassis.

The lights that are currently installed are:

• Side Marker - 10 W
• Front Top - 8W
• Front Bottom - 23W

Thanks!

 

[45Dougal]

Seems like they're wired up incorrectly - maybe send a photo of the inside.
The fact that the top bulb is only 8W, probably explains why they're not flashing.
If you switch the 21W bulb into the top slot then they should flash. Albeit with the white bulb.
Then rewire them and switch the bulbs back.

 

[MatthewMcD]

Seems like they're wired up incorrectly - maybe send a photo of the inside.
The fact that the top bulb is only 8W, probably explains why they're not flashing.
If you switch the 21W bulb into the top slot then they should flash. Albeit with the white bulb.
Then rewire them and switch the bulbs back.

Thanks, rewiring is complete on the driver's side and EVERYTHING IS WORKING!

The passenger side is going to be a bit more work as the wiring is trashed and the lights are very dim. I'll run new wires and (if necessary) resolder everything. Pretty sure we figured out the issue.

It was your mention of the "21W bulb" for testing that got me thinking this way. Thanks @45Dougal !!

Now, if anyone knows were to get gaskets for these light assemblies...

 

[MatthewMcD]

Ok, Cleaned up the passenger side light. Stripped out the PO splice and corrected the incorrect wiring arrangement. Everything is working. Solid grounds and bright running lights. Blinkers blink and hazards hazard!

Need to add to the basic troubleshooting list, "Are the correct lights wired as blinkers?"