I had the same exact problem and it was loose/bad connection in the Hazrd Switch and the connector itself just plain worn out.
Ok, Uncle. Turn signal/hazard problems (1 Viewer)
- Thread starter subzali
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Rockets2000
Space Cadet
This is very much the same path I had to take, and eventually had an "ah-ha" moment after I cleaned my fuse block and replaced all the fuses. Scour the schematics and take notes as to what color wires you have going into and out of the connectors and switches, then check them all per the schematics. I know that's what you've been doing, but if you keep looking, you'll eventually stumble on the answer. Might just be that GW wire. The schematics don't show the connectors....Turns out my Haynes manual has had better info than the FSM on details of the wiring diagram. I have compared the wiring diagrams for '76, '77, and '78 in the Haynes and see some subtle differences. My FSM has the wiring diagram for a '79 (inconvenient since I supposedly ordered an FSM for a '77), which also has some more differences. According to Haynes, a '77 should have a "GR" power from the "turn" fuse for when the hazard switch is "off" and a "GR" power from the "stop" fuse for when the hazard switch is "on." Instead, I have found that I actually have a "GO" power from the "turn" fuse for when the hazard switch is "off." But that really is neither here nor there, the color of the wires is somewhat immaterial (though inconvenient when it doesn't match the wiring diagram) as long as the path for electricity to flow is completed.
I'm slowly pulling all the info in the FSM together - connector pin continuity, wire colors, etc. I think I have a pretty good understanding of how it's SUPPOSED to work, but I'm having trouble finding out why MINE doesn't work, even though it seems to be hooked up correctly. I'll start with the turn signal switch and then deal with any other problems as they come up in the diagnostic process.
Jacket
Moderator
Screw it - you'll never figure it all out with the body panels in the way. Time to pull the tub off and start the frame off. 
- Thread starter
- #24
Ha ha you're funny Matt 
So after cleaning my turn signal switch a little bit more yesterday I was able to get my right turn signals to come back regularly when I put it back in this morning. So now I have both left and right turn signals. But only when my hazard switch is pulled to the "on" position. My 4-way hazard function still does not work. Any ideas? I'm getting power from my "Stop" fuse to my hazard switch (hazard "on"), and from my hazard switch to my flasher, and the rest of my contacts in the hazard switch are good, so shouldn't the power be going through all the way to the 4 corner bulbs?
Another question: There was (what I assume to be) dielectric grease inside both the hazard and turn signal switches. Do I need to put some new grease in there or ???
So after cleaning my turn signal switch a little bit more yesterday I was able to get my right turn signals to come back regularly when I put it back in this morning. So now I have both left and right turn signals. But only when my hazard switch is pulled to the "on" position. My 4-way hazard function still does not work. Any ideas? I'm getting power from my "Stop" fuse to my hazard switch (hazard "on"), and from my hazard switch to my flasher, and the rest of my contacts in the hazard switch are good, so shouldn't the power be going through all the way to the 4 corner bulbs?
Another question: There was (what I assume to be) dielectric grease inside both the hazard and turn signal switches. Do I need to put some new grease in there or ???
It sounds more like your hazard switch is either fudged or wired incorrectly. When you pull it out, it selects the stop fuse as the power source and connects the flasher output directly to the L and R turn wires. This bypasses the turn signal switch, so if your turn signals only work when the hazard is pulled out, something is wrong. I would not anticipate that Toyota used the wrong color code wires or changed them much over the years. The colors fade however.
What I would do is to isolate problems that are downstream from the flasher. The power output wire from the hazard switch is the G/O wire. Put 12V on this wire and turn the turn signal switch on. With the hazard pushed in, the turn should flash on the side the switch is turned to. When the hazards are pulled all 4 should flash. If not, there is a problem down stream from the flasher.
If Everything downstream from the flasher works, then you can concentrate on the hazard switch and the wires from the fuse block.
What I would do is to isolate problems that are downstream from the flasher. The power output wire from the hazard switch is the G/O wire. Put 12V on this wire and turn the turn signal switch on. With the hazard pushed in, the turn should flash on the side the switch is turned to. When the hazards are pulled all 4 should flash. If not, there is a problem down stream from the flasher.
If Everything downstream from the flasher works, then you can concentrate on the hazard switch and the wires from the fuse block.
Cruiser804
SILVER Star
Maybe I missed it. Not sure why you haven't considered the bulbs there are a number of threads here by "experienced people" that that lead to the bulbs or fuses creating these types of issues.
Now that you know everything is wired correctly its the next logical place to look. Although, I would have started with the simplest solution first. But that's just me.
Now that you know everything is wired correctly its the next logical place to look. Although, I would have started with the simplest solution first. But that's just me.
- Thread starter
- #27
I have considered the bulbs and have checked/replaced them, as well as the fuses, as well as the grounds. But beyond that, the bulbs don't care whether the power is coming from the turn signal circuit or the hazard circuit, the voltage looks the same either way by the time you get to the bulbs. But just in case I missed something, I'll do it again.
Anybody have input on whether to use some more dielectric grease in the switches? What about the bulb connections?
Anybody have input on whether to use some more dielectric grease in the switches? What about the bulb connections?
Cruiser804
SILVER Star
True the bulbs don't care but a hand full of worn bulbs combined with tired wiring and worn switches can create enough resistance to cause issues with the flasher. I believe the hazards and the turn signals run off two different fuses. The turns signals are on a ignition and the hazards direct to the battery. So one may work while the other doesn't.
My issue was very similar. Hazards worked, turn signals worked but the turn signals would not work with the lights on. I replaced every bulb, headlights were already new, I mean every bulb, stop, turn signal, reverse. Mostly because I was already there. I used dab of dialectic grease when I rebuilt the headlight witch and put dab on all the bulbs.
My issue was very similar. Hazards worked, turn signals worked but the turn signals would not work with the lights on. I replaced every bulb, headlights were already new, I mean every bulb, stop, turn signal, reverse. Mostly because I was already there. I used dab of dialectic grease when I rebuilt the headlight witch and put dab on all the bulbs.
Last edited:
So, Im about to tackle recreating this circuit with new wire and a Kwik Wire harness. I have dissected this area out of the main harness to see what wires are going where. Wondering if anyone can chime in on the G/W wire with the male bullet connector, cant find an answer to where this wire goes. And for those that have swapped a universal harness in, is it easier to keep the OEM hazard/turn relay in recreating this circuit, rather than utilizing the built in relay in the new fuseblock?
Bullet connectors are used where there is a single wire connecting to a device, like the idle fuel cut off solenoid, for example. The '76 schematic indicates that the wire from the horn relay to the horn is G/W and I would expect it to have a bullet connector on the horn side. There is also a G/W wire from the emission computor to carb thermo sensor.
Last edited:
Hoping to get some help.....
Hi, I just registered after reading this post. I have an almost identical issue as this original post. Difference is my hazards work fine. I have ran all the checks listed here, but my turn signals left or right will not work. I have a new turn signal switch and I have 12 volts with the key on at the Flasher both wires. I have 12 volts at the G\Blue or GL if that is the same wire at the turn signal; however, when I apply that 12 volts to the turn signal wire left or right it immediately drops to 0 volts and the flasher never kicks in. This is through the turn signal switch or directly connected G\Blue to B\Black (Lft Turn) or G\Y (Rt Turn)
Like the gentleman that posted here I have six wires in my turn signal harness, but only four on the truck side and everything looks stock like it is supposed to be that way. After running down the entire hazard switch wiring, existing turn signal wires and reading all of the great info in this post, I feel like I understand how this is supposed to work. What has me stumped is why the voltage on the G\Blue wire drops to zero when connected to a load... I even used just a 12 volt single filament light to rule out any bad wiring or bulbs and got the same results and Are the other wires in the turn signal switch supposed to be connected to anything?
So I have all of the voltages as they should be and my flasher switch and flasher work properly flashing my lights, but no love with the turn signals, even though I show 12 volts on the G\Blue flasher wire.... What am I missing???? Please help!
Thanks for any help y'all may provide.... I am at my wits end.
My name is Steve and I have a 77 FJ40.
Hi, I just registered after reading this post. I have an almost identical issue as this original post. Difference is my hazards work fine. I have ran all the checks listed here, but my turn signals left or right will not work. I have a new turn signal switch and I have 12 volts with the key on at the Flasher both wires. I have 12 volts at the G\Blue or GL if that is the same wire at the turn signal; however, when I apply that 12 volts to the turn signal wire left or right it immediately drops to 0 volts and the flasher never kicks in. This is through the turn signal switch or directly connected G\Blue to B\Black (Lft Turn) or G\Y (Rt Turn)
Like the gentleman that posted here I have six wires in my turn signal harness, but only four on the truck side and everything looks stock like it is supposed to be that way. After running down the entire hazard switch wiring, existing turn signal wires and reading all of the great info in this post, I feel like I understand how this is supposed to work. What has me stumped is why the voltage on the G\Blue wire drops to zero when connected to a load... I even used just a 12 volt single filament light to rule out any bad wiring or bulbs and got the same results and Are the other wires in the turn signal switch supposed to be connected to anything?
So I have all of the voltages as they should be and my flasher switch and flasher work properly flashing my lights, but no love with the turn signals, even though I show 12 volts on the G\Blue flasher wire.... What am I missing???? Please help!
Thanks for any help y'all may provide.... I am at my wits end.
My name is Steve and I have a 77 FJ40.
Are you measuring voltage from a given terminal to ground or are you measuring across a device (like a switch)?
What other wires at the turn signal switch are you asking about? I see that there should only be GL (incoming power from the flasher) and GB (left) and GY (right).
What other wires at the turn signal switch are you asking about? I see that there should only be GL (incoming power from the flasher) and GB (left) and GY (right).
I am measuring voltage at the G\Blue wire directly to ground. I have 12 volts with the key on, but immediately drops to 0 when connected to any load.
The other wires in the turn signal switch are:
G
G\W
G\O
G\R = Horn
When in a left turn configuration, these wires are in the circuit G\Black, G\Blue, G Out of the circuit are G\W & G\O
Right turn = G\Y, G\Blue, G\O out of the circuit G\W & G\O
Thanks for the quick reply!
The other wires in the turn signal switch are:
G
G\W
G\O
G\R = Horn
When in a left turn configuration, these wires are in the circuit G\Black, G\Blue, G Out of the circuit are G\W & G\O
Right turn = G\Y, G\Blue, G\O out of the circuit G\W & G\O
Thanks for the quick reply!
Do you have the wiring diagram? I'll post one, if you don't.
This is a diagram that was already on-line in the Tech Links and I assume to be somewhere around late '76 to '78, since it has an ignitor. The wiring and wire colors didn't change much during that time. I did notice a difference between my '76 and my '78 diagrams, in that the wire from the F terminal of the Hazard Switch to the B terminal of the flasher is GO in '78 diagram and GW in '76 diagram. It's not labeled on this pdf diagram.
http://www.ih8mud.com/tech/pdf/fj40_wiring_diagram.pdf
You will find that switches and other devices, OEM and aftermarket, sometimes have different wiring colors than the harness itself, but typically the wires are in the correct locations in the plugs for the function. I just looked at a '76 column that I have out and the 6-pole plug for the turn signal switch has GY, GB, GO, GL, GR, and G wires. There is also a 4-pole plug with RY, RG, and WB wires and a single GW bullet connector. I'll have to do some additional research, since I've noticed that the wiring doesn't necessarily match the wiring diagram, as other noted earlier in this thread.
http://www.ih8mud.com/tech/pdf/fj40_wiring_diagram.pdf
You will find that switches and other devices, OEM and aftermarket, sometimes have different wiring colors than the harness itself, but typically the wires are in the correct locations in the plugs for the function. I just looked at a '76 column that I have out and the 6-pole plug for the turn signal switch has GY, GB, GO, GL, GR, and G wires. There is also a 4-pole plug with RY, RG, and WB wires and a single GW bullet connector. I'll have to do some additional research, since I've noticed that the wiring doesn't necessarily match the wiring diagram, as other noted earlier in this thread.
Correction on the Right turn In circuit is G\Y, G\Blue, G\O. Out of the circuit is G\W and G NOT G\O
Interesting. I've never looked into this before, because I've never had the need to. Based on the switch diagram I just found in the Body and Chassis manual, Toyota has wires for both the front and rear turn circuits going to the switch (rather than just a single wire for each function at the switch). This explains the additional wires that you mentioned. So, your 6-pole connector has power from the flasher (GL), front left turn (GB), rear left turn (G), front right turn (GY), rear right turn (GO), and horn (GR). The 4-pole connector in the assembly is power to the headlight Hi-Lo switch (WB), Hi beam (RY), and Lo beam (RG). The single GW bullet, listed as power to the stop light switch on the diagram below, was not connected in the '76 column that I'm looking at.
I just looked at the associated 6-pole connector in the truck harness and it does, as you mentioned earlier, have only four wires. It has GB for left turn, G for power (mates with GL of the switch), GY for right turn, and GY (yes, GY) for the horn. Toyota did some funny stuff over the years. I don't know what they were thinking here, but it looks like they didn't actually use the rear turn signal wires that are attached to the switch. Huh.
Anyway, see if you can light the right and left turn signal bulbs just by applying 12v to the associated GY or GB wires at the harness plug (and ground to the frame or body, of course). That'll rule out any issues from the column connectors to the lights. If they light up OK, then you can look at the switch further.
I don't know what they were thinking here, but it looks like they didn't actually use the rear turn signal wires that are attached to the switch. Huh. Anyway, see if you can light the right and left turn signal bulbs just by applying 12v to the associated GY or GB wires at the harness plug (and ground to the frame or body, of course). That'll rule out any issues from the column connectors to the lights. If they light up OK, then you can look at the switch further.
