I have a 1990 4runner v6 and no brake lights.

There are a few possible reasons why your turn signal light is not working while your brake and tail lights are functioning properly:

1. Blown fuse: The turn signal lights are connected to a different fuse than the brake and tail lights. The fuse for the turn signals may have blown and needs to be replaced.
2. Turn signal switch: The turn signal switch, located on the steering column, could be malfunctioning and needs to be replaced.
3. Wiring issue: A wiring issue, such as a broken wire or loose connection, could be preventing power from reaching the turn signal lights.
4. Flasher relay: The flasher relay is responsible for controlling the turn signal lights. A faulty flasher relay could be preventing the turn signals from working.
5. Signal/light module: Some cars have a signal/light module that controls the turn signals, this could be faulty and need to be replaced.

Change the bulb.The bulb has two lights.Running,and brake light turn signal.Its the bulb

WHEN YOU APPLY BRAKE PEDAL, do you see brake lights come on ? if no then the switch is not working fine ! switch turns lights on when you depress the pedal, releasing the plunger, lights go out when you release the pedal. this switch has a fuse @ fuse block. check it ! if ok, and brake lights do
not come on replace switch, & mount properly in bracket.

I assume the fuse has power if the hazards work.
The third brake light skips the turn signal switch, the regular brake light circuit goes thru the turn signal switch.
Do you have power going into the turn signal switch on the red lite green wire from the brake switch ?

Turn signal tail lights and BRAKE LIGHTS NOT WORKING

It can be faulty brake light switch causing the problem or its blown brake light bulb. First check and confirm brake light lamp is working and that's not the case.

For turn signal not working it can be faulty turn signal switch or its issue with wiring:----

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To trouble shoot brake and turn signal related problem, check the help links mentioned below:-----

Click the link:----
1996 Buick Regal Grand Sport Brake light Switch Location? http://schematicsdiagram.blogspot.in/2012/04/1996-buick-regal-gran-sport-brake-light.html

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No brake lights on Buick? http://schematicsdiagram.blogspot.in/2012/04/no-brake-lights-on-buick.html

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Brake lights not working on 1989 BUICK REGAL?

http://schematicsdiagram.blogspot.in/2012/04/brake-lights-not-working-on-1989-buick.html

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How to replace Brake light switch on Chevrolet Tahoe?

http://technoanswers.blogspot.in/2012/02/how-to-replace-brake-light-switch-on.html

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How to replace Parking, turn, and Brake Lights on car?

http://schematicsdiagram.blogspot.com/2011/06/how-to-replace-parking-turn-and-brake.html

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Upper brake lights work, but low brake light not working?

http://schematicsdiagram.blogspot.com/2011/12/upper-brake-lights-workbut-low.html

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1997 Cadillac Catera: How to replace Brake Light Switch?

http://howtobyme.blogspot.in/2012/06/1997-cadillac-catera-how-to-replace.html

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2003 Chevrolet S10 Tail light Fuse http://schematicsdiagram.blogspot.com/2012/11/2003-chevrolet-s10-tail-light-fuse.html

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Chevrolet Parking light and Tail lamp light Wiring diagram http://schematicsdiagram.blogspot.com/2012/11/chevrolet-parking-light-and-tail-lamp.html

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Car Tail Lights Not Working?

http://schematicsdiagram.blogspot.com/2011/12/car-tail-lights-not-working.html

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Turn Signal Not working http://technoanswers.blogspot.com/2012/11/turn-signal-not-working.html

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Right turn signal not working on Pontiac Car?

http://schematicsdiagram.blogspot.com/2011/12/right-turn-signal-not-working-on.html

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Only one side indicator light working on car?

http://schematicsdiagram.blogspot.com/2011/12/only-one-side-indicator-light-working.html

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Turn signals not working on 1987 Jeep Wagoneer? http://schematicsdiagram.blogspot.com/2011/12/turn-signals-not-working-on-1987-jeep.html

1996 Chrysler LHS brake light circuit wiring diagram?

http://technoanswers.blogspot.in/2012/02/1996-chrysler-lhs-brake-light-circuit.html

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How to replace rear Brake lights on 2004 Toyota RAV4? http://schematicsdiagram.blogspot.in/2012/02/how-to-replace-rear-brake-lights-on.html

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One brake light on driver side not working, but other lights work?

http://schematicsdiagram.blogspot.com/2011/12/one-brake-light-on-driver-side-not.html

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2002 Lincoln Town car Fuse Box http://schematicsdiagram.blogspot.com/2012/11/2002-lincoln-town-car-fuse-box.html 2007 KIA Rio: Brake Light Fuse Box Diagram?

http://repairhelpcenter.blogspot.in/2012/06/2007-kia-rio-brake-light-fuse-box.html

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Overhead Brake lights not working on 1999 GMC Sierra 4x4?

http://technoanswers.blogspot.in/2012/03/overhead-brake-lights-not-working-on.html

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2004 Ford Mustang: Brake light Fuse Location?

http://howtobyme.blogspot.in/2012/05/2004-ford-mustang-brake-light-fuse.html

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These will help.

Thanks.

I would check for voltage at the turn signal switch. The brake lights go thru the turn signal switch, except for the high mount light.

COULD HAVE FAULTY BRAKE LIGHT SWITCH OR BAD GROUND WIRE AT BRAKE LIGHTS AND TURN SIGNAL LIGHTS.

I've worked on these the first drove me crazy. its the turn signal switch every thing runs thru these. head lights, turn signal, brakes. except the third brake light. it runs directly from the brake switch. go figuare

Hi!!

If you activate the turn signal switch and you step on the brake pedal, the turn switch (on the steering column) deactivates the brake light to make the signal light more visible. The bulb for the stop and turn lights is the same.

Turn hazard lights ON. If they don't blink, replace turn/hazard flasher, If one or more lights don't come on, replace bulb.

Check fuse and circuit wiring for broken or loose connections. If all looks fine, check following:

If front turn lights work fine, check brake/turn bulbs.

If turn lights come on but don't blink, replace turn signal/hazard flasher.

If front and back turn lights don't come on, replace switch on column.

Let me know how it worked out, Good Luck

I had the same problem about a month ago myself. I had to replace a fuse which was under the driver side under the dash it cost me $6 to replace. I cant remember the name of the part but call a auto store and explain to them the problem. I think it was called a relay fuse or something! Good luck with that!