Turn signals and brakes work but not at same time???

[KEEJEF]

Not sure what is going on but my rear turn signals work both left and right but quit flashing when I apply the brakes. I have a converter box that takes the separate turn and stop down to combo turn stop and have it wired up correctly. I even thought it might be the converter and replaced it but still having the same problem. Any help would be appreciated. Also when I turn on the hazard lights the front signals flash but not the rear. I am sure there is something here pretty obvious but I have not figured it out yet!! Thanks again for any help you guys can give.
Jeff

 

[pcruzdad]

I had the same problem after installing all new tail lights. I would turn on the blinker and it would work fine untill i hit the brakes, then it would stop flashing. The first thing i would check make sure you have good grounds, if you're not grounded well you can have alot of problems with your light. I'm pretty sure that was what my problem was but if i remeber something else ..... well one of the lifers will have you fixed up by then. they blow my mind

 

[Pin_Head]

You shouldn't need a "converter" box, so something is not stock. What year is it and what non-stock components do you have?

 

[Vicm]

Like Pinhead said ,because of lack of details and the use of a converter.
What year , what taillights used , and why a converter? Is it a post 74 on a pre 74 frame?
The turn signal flasher will work as long as there are 2 bulbs or more wired right. And it doesn't matter which 2. In this case the front 2 are wired correctly. So your problem is in the rear.
More details needed.
Vic

 

[KEEJEF]

I have a 75 FJ40 and it does have the separate turn and stop wires. I have the green w/yellow stripe for the right turn signal, green w/black for the left turn signal, green w/white stripe for brake lights and solid green for running lights. The converter takes these and combines to combo turn stop to my sealed aftermarket rubber mounted lights in my fabricated rear bumper. I did notice something else last night after going over the wiring diagram. There is a green w/white stripe wire running from the signal switch on the column that looks to have been messed with at some point. I can't find where it should be going but it is obviously not the way it was from the factory. This could be part of the problem. From reading some of the other issues on the forums it looks like the hazard light switch plays a big role in the flashers working and could be part of my problem. Thanks in advance for all the help.
Jeff

 

[KEEJEF]

Forgot to mention that I have checked all the grounds by running a separate temporary wire from each light ground point back to the battery ground and still having same issue.

 

[Coolerman]

I don't know if the 75 wiring is exactly the same as a 78 but 78 wiring appears to be close.

Go here: Coolerman's File Retrieval and download the 78 schematic. It is a pdf file, so you will need the Adobe reader installed to view it. I would also grab the 71 schematic (71fj40_wireCleanedM.tif) it shows how the older trucks with the combo lights are wired.

The later hazard switch does nothing but provide two sources of power to the turn signal/hazard relay. If the hazard switch is OFF, power is provided to the relay via the wiper/turn signal fuse which is only hot when the key is on. If it's ON, power is provided through the Stop light fuse which ALWAYS has power. Be aware: The Hazard lights, when on, will override the turn signal switch completely.

The only Green/White wire I see is the power feed coming into the Hazard switch on terminal B. This wire originates from the Stop light fuse.

 

[Pin_Head]

So:
You are running both the stock '75 rear lights and the aftermarket lights in the bumper at the same time?
When the front hazards blink, the rears do nothing or light up and don't blink?

So what kind of steering column do you have? On a '75, there is no stop light wire (green/white) that goes to the column. Earlier Toyota columns (4 wire w/common stop and turn filament) had the brake light wire in the steering column. GM steering columns have this arrangement too. These columns are not readily compatible with later 5 wire systems.

Some cheap 5 wire to 4 wire trailer conveters allow the stop lights to over ride the turn signal. A good converter should cost about $35-50.

Why not just let the after market lights be turns or stop lights but not both?

 

[Coolerman]

Pin_Head, do you (or anyone else) have a 75 OEM schematic in digital form you could send me? It's one I do not have, and can post it to my list.

 

[KEEJEF]

I am only running the combo turn/stop lights in the rear bumper and not the factory rear turn/stop/backuplights. I have the converter in place and wired correctly. The harness coming from the turn signal switch in the column (stock 75' column) has this green/white stripe wire in the factory loom. The wires in the loom go to a white connector but there does not appear to be any wires missing from the connector where the green/white would have gone. I am still thinking it could be something in the hazard light switch since the rear lights don't flash when the hazards are on. Thanks again for the help.
Jeff

 

[Vicm]

Honestly from your disctriptions , I would say the connections are good as far as Haz switch , flasher, and signal switch.
Because it is doing what it supposed to do.
This is what I suggest you do to save time.
You can try this on one side only.
Take the converter out of the wiring and and wire straight to the bulbs. You have 2 of them. So wire one as stop light and the other ar a turn signal, then see how they function.
If everything works like it should then you know the problem is from the converter or the way it is wired.

The Green/ w wire should be like you already said between the Haz switch and stop fuse. It feed power from the stop fuse to the flasher when you pull the haz switch.
When the Haz switch is pushed the power to the flasher comes from the turn signal fuse via the green/red wire instead.
There are 2 side to the Haz switch so it is realy 2 switches in one.
I have posted a diagram that shows those 2 positions few months back, but I couldn't find it .
Your solution I think is right , you need the converter , because you need to the use the one filemnt bulb to do both ,stop and blink. Like most domestic cars.
If you had a 2 filment bulb instead , it would have been a simpler connection.
I don't know if this all make any sense.
Sometimes, I find it hard to explain things, English not being my mother toung.
Vic

 

[Pin_Head]

How many wires do you have at the steering column connector and what are their colors? On a 75 column, there is just a single green/yellow and green/black wire and the front and rear wires are connected together, so that when one flashes, the other one must too. If only the fronts flash, someone must have cut or disconnected the rears.


On earlier "4 wire" columns, the front and rear wires are separate and different, although they have the same color code, so there are two of each at the connector. They also have a single green/white wire to run the brake lights.

 

[KEEJEF]

Thanks for all the help so far. Here is the latest. I took the converter out of the wiring and wired a temporary extra light for the turn signals on the rear (one left and one right). Now it is wired the same as factory with stop and turn separate. The hazards flash as they should front and back. But when I turn the signals on left or right the signal lights are solid and do not flash. Pushing the brake now has no effect on the flasher like it did before but still can't get flashers to work. One thing I have not mentioned that could be playing a role in this problem is I do not have the factory front turn signals but have installed some very small flush mount ones on the fenders. They still have the dual element for running and turn signals and are grounded as well. Is there a chance the flasher could work fine with hazards since there is the load of all the signals at once but when just right or left is on the load is not enough to make the flasher work? I know little about the flasher except for I am pretty sure it is based on load and some sort thermal properties. Since the lights do stay solid when the signal is turned on I suppose the wiring is okay through the hazard to the flasher to the signal switch and onto the signal lights. Thanks again for any help on this. I think I am close but have just about exhausted all the little knowledge I have on this one!!
Jeff

 

[Pin_Head]

The flasher needs a minimum current load to heat up the bimetal switch. If the front lights have two filament bulbs, maybe you aren't using the right one. You could also use both filaments, which would increase the current load.

The other option is to get load insensitive solid state flasher.

 

[Coolerman]

Here is a simplified pic, is it yours Vicm?

It's possible that the new lights pull less current. You can test that theory by putting another light in parallel with one of the front turn signal lights, and see if it now flashes.

 

[Vicm]

Now take the front bulbs out of the picture and try your Haz again, if they stay solid , you need higher watt bulbs in the rear try somthing close to 30.
As far as the flasher it is definatly good.
The flasher is always connected to your bulbs, but because of the resistance that heats the steel spring taking most of the current the bulbs do not light, till the spring is heated enough to bend and and close the contacts bypassing the resistor, now the current lights the bulbs. And the cycle starts again once the spring is cooled and the contacts are opend.
Good diagrams above by the way.
I do have some info about the difference between turn flasher and Haz flasher, I will send it to Coolerman once I get all sorted out. I think Pinhead or Coolerman can explain things better .
Vic

 

[KEEJEF]

I really appreciate the time you guys have put into replying to my problem. I think the solid state flasher might be the answer. Any ideas on which one to get?
Jeff

 

[Vicm]

I really appreciate the time you guys have put into replying to my problem. I think the solid state flasher might be the answer. Any ideas on which one to get?
Jeff

Not saying that won't work, but you will fix your problem by using 27W bulbs. Much cheaper, unless these taillights are LED type.

 

[steverb]

my truck has the converter. i use to have problems with the turn signal i ended up replacing the flasher with a stock one from toyota and replaced the wiring all the way up the frame to the first conecter on the firewall. the problem went away.

but i also don't have hazards in the back only the front.

 

[Vicm]

After having more time to think about all of this, I am starting to believe that you have older than 74 signal switch , I am not sure about the wiring for them, but I see in my diagrams grren/w wire coming from the signal switch.
Someone with this type of switch can verify , but the 74 and up , the signal switch will have only 6 wires, 3 red based those are for lighting and 3 green based for the signals.
The older switch will have more than 3 wires for the signals.
This mix will definately make the brake effect the blinkers,because in the 4 wire tail, the signal switch does the job of cotroling the brake circit along with the signal circits. Something to think about. I am not 100%, because I have never seen the older signal switches, just looking at diagrams.If this is true , then you won't need the converter , you just have to rewire everything.
Vic