Brake light HELP!

Discussion in '40- & 55-Series Tech' started by Borrego, Aug 10, 2017.

  1. Borrego

    Borrego

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    I have a 71 FJ40 (built in Sept 1970). All of a sudden my brake lights went out. The running lights and turn signals work. The hazard lights have never worked, and now the brake lights don't work.

    I suspect it's the brake light switch. I'm newer to electrical and may need help understanding the schematic but I downloaded the wiring diagram posted by Coolerman, and noticed it shows only 2 wires coming out of the brake light switch, a RW and a GW. The RW is going to the 20amp fuse, and the GW is going to the turn signal switch. When I look at my brake light switch, it has 4 wires (2 RW and 2 GW). And neither of them go directly to the fuse block or the turn signal switch. Instead, the brake light switch plugs into 6 wires (a multitude of GW and GY wires). It looks like this is stock, but it doesn't align with the schematic. Can anyone please help me understand what wire is what, because I can't figure it out with the schematic.

    Thanks!
     
  2. shawnfj40

    shawnfj40

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    I assume you have checked the bulbs? The next step is the fuse. Then check for power at the switch. Then check switch operation (see if it works). You are going to have power on at least one of the wires on the switch at rest, it should increase to more than one when the pedal is depressed. If they just stopped working all of the sudden its probably a fuse or bulb issue.
     
  3. Borrego

    Borrego

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    Checked the fuse, it's good. Checked the bulbs, both filaments work. (Blinker works and running lights work). Checked grounds at the lights, they are good. It's just the brake lights that don't work. I bought a new brake switch and still nothing. I pulled the hazard switch and checked all the solders, and they look clean as a whistle. (however, my hazard lights don't work, and never have since I've owned it, even when the brake lights DID work, the hazards did not. I checked the flasher and believe it works because the turn signals work. The turn signal was all cut up by a PO, but all the connections look solid.

    What else should I check? It's been months and I still don't have brake lights. I only drive it during the day now, and turn the running lights on every time I come to a stop so it looks like I have brake lights. LOL. I want this fixed!!! Is there a way to bypass all the other switches and go directly to the brake lights just to test things?

    Also, the wiring schematic for a 71 I pulled from @Coolerman only shows 2 wires for the brake switch. Mine has 4 wires on the male end factory plug and 6 wires on the female end of the plug. It looks factory. Does anyone have the correct schematic for a 9/71 that shows this?

    Any and all help is much appreciated. Even a quick fix just so I can drive it through the summer would be helpful. I'm at a loss and ready to throw in the towel and try to rewire the whole thing, but would prefer to wait until fall/winter to do so.

    Thanks
    Eric
     
    Last edited: May 16, 2018
  4. 73FJ40

    73FJ40 After another night of rust removal! SILVER Star

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    I think you may need a later model schematic. Also note that Toyota wiring diagrams are notorious for their 'lack of accuracy'. In some instances, there are major differences for the same model year between USA market and world market FJ40's.

    Note that the brake switch you describe, 2 GW, 2 RW is consistent with the brake switch used from 7007 (July '70) to 7509.

    upload_2017-8-11_11-24-40.png

    You may want to consider using a later year wiring diagram, like this one:

    http://www.globalsoftware-inc.com/coolerman/fj40/schematics/FJ40/1974FJ40/HaynesFJ401974.jpg
     
    Last edited: Aug 11, 2017
    shawnfj40 likes this.
  5. shawnfj40

    shawnfj40

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    The hazard switch not working is a concern as well. Almost everything in your lights routes through that switch. they are notorious for the contacts getting corroded and not making contact. They are pretty simple to clean and I think coolerman has a how to on it. I know someone did a nice writeup on it. Like was said before if you haven't had the rig since new its hard to say if it even has the original wiring harness in it. I have changed out a few just because they were so chopped up by PO that it made better sense to replace than to repair them. Odds are you have a 40 harness. You just need to find the right year it is.
     
  6. espensen

    espensen

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    This is the plug the brake switch connects to. The upper two connections are for the brake lights, the two below are for the brake warning light. You should have power on the upper left pin. If you have, you can try to connect the two upper pins together, if the brakelights don't lights then, you have another problem after that... Maybe your turn switch


    DSCF5154[1].JPG
    Maybe this is diagram is better? 343ElectricalWiringDiagramFJ40(L)x.jpg
     
  7. Borrego

    Borrego

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    Life has happened, and it's been awhile since I've been able to touch this... I don't drive it often, and when I do it's just during the day, and I pull my running lights on when I need to show brake lights around town. LOL.

    So, Since the last posts, I've checked the hazard switch, and all the contacts looked clean as a whistle, so I don't think the issue is there. My turn signal wiring was cut by the PO, so I don't have the original plug, but the splices all look in good contact and I can trace the wires back into the factory harness and they look like they go where they should.

    When I check the upper left pin on the picture above, I only get power when the ignition is on, and my test light shows a very weak light (it barely lights up, but it does light). All other pins have nothing, and when the ignition is off, there is no power at all.

    What I don't understand on the above schematic is how this picture (option) ties in... What are Fuse A and Fuse B, and what wires go to the turn signal switch, hazard switch or brake lights?
    upload_2018-5-16_8-49-16.png
     
  8. 4x4veteran

    4x4veteran

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    With a 12V test light check the hot wire in the socket using a good ground.
    If you get a light then clean the socket and see if a known to be working bulb lights up.
    If you can't get power at the tail light socket work your way forward tracing the wires looking for breaks and bad connections and testing with the light.
    I am betting bad ground at the brake light.
     
  9. Borrego

    Borrego

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    I'll give it a try tonight, but I'm pretty sure my grounds are find at the lights, because I believe it to be a 2 way light, running light on one wire, and brake/turn signal on the other wire. Turn signals works. So wouldn't that rule out anything at the light socket?
     
  10. espensen

    espensen

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    You should have power on upper left pin regardless as the ignition is on or off. So it seems you have a problem with the wire from the fuse to the switch. Have you checked the fuse (2nd from the top)? Its the same fuse as the horn, does your horn work?
     
  11. Borrego

    Borrego

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    I have no power to any of the pins with the ignition off. I checked the fuse and it is fine, and my test light lit up when touching the "down river" side of the fuse terminal, so I know all is good there. I jumped a wire directly from the fuse terminal to the upper left pin and my brake lights came on! When I pushed the brake light switch in, they went off. IT WORKS! So that fuse provides power to the horn, hazard switch, and brake light switch (none of them work). I guess it would be safe to say it's probably an old broken wire going to one of those. I am going to try jumping the hazard constant as well and see if the hazards work. If they do, I'm going to rewire that whole circuit (horn, brake switch, hazard). Do you know where the horn relay is located?
    Thanks for your help!!!
     
  12. Coolerman

    Coolerman SILVER Star

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    The wire from the F2 fuse (Horn/Brake/Cigar Lighter Fuse) is GW and goes from the fuse panel, straight to the brake light switch upper left terminal. If you don't have power on that terminal, either the wire is broken between the fuse panel and the connector or the fuse is not making good contact. So first thing you need to do is remove the F2 fuse and clean the fuse contacts then install a new fuse. If that doesn't work then you will have to replace that wire or at least figure out where it is broken. I would first look at the terminal crimps on each end of the wire.

    The horn relay is located on the passenger side inner fender. Look for the three pin connector that the relay plugs into.

    Also be aware that the Hazard switch has a hidden fuse. It is located in a clear plastic fuse holder that is taped to the main harness behind the heater. Just follow the fuse panel wires back to the main harness and you will see it. This is a 10 amp fuse.
     
  13. Borrego

    Borrego

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    Well, I thought I had it figured out... LOL.
    So is this the wrong schematic? On here it looks like the F2 fuse is Horn/Brake/Hazard. I was able to locate the 10amp hazard fuse, and it looked good, but I had no power going to either end of it with my test light. Should that have constant power or ignition power? I don't see it in the schematic.

    upload_2018-5-23_9-32-37.png
     
  14. Coolerman

    Coolerman SILVER Star

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  15. Coolerman

    Coolerman SILVER Star

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  16. Borrego

    Borrego

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    Thank you all! With all your guys help, I think I'll be able to fix it tonight!
     
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