Brake light question (1 Viewer)

[Robcat]

I recently picked up a '70 FJ40 that spent its life as a farm truck, and has never been driven on a public road. As such, having functional lights/turn signals/brake lights was obviously not a priority to the PO. After much effort (and a huge debt of gratitude owed to Coolerman for his wiring diagrams), I have everything working EXCEPT the brake lights.

Here's my question:
The brake switch is working perfectly, and I have power through the gw wire going into the turn signal switch when the pedal is pressed. Given that the rear signals are working, is it safe to assume that my issue is in the switch? Probably a stupid question, but I'm learning as I go, and I've learned not to make assumptions.

Thanks!

Rob

 

[Robcat]

I tried to post a pic, but I'd rather spend the time figuring out how to fix my brake lights than learning how to post images.

I just pulled off the back of the switch, and there are no obvious problems; nothing scorched, tweaked, melted, or broken.

 

[Robcat]

Here's the pic I just got through saying I couldn't post. I've been looking at wires for so long, it's a wonder I can even type at this point.

 

[DSRTRDR]

check the grounds of your brake lights, and of your blinkers if they are separate - are the bulbs seated properly ?

 

[Robcat]

I just purchased the tail lights from SOR, and everything tests out including the bulb. I've dealt with enough old cars to NEVER rule out a ground issue, but if that was the case, would the turn signals work? I'm fairly certain the signals activate the same filament as the brake lights.

 

[DSRTRDR]

do the hazards work ?

the brake wiring is in the circuit with blinkers and hazards - hazard switch would be worth looking at, too

the plunger on the brake switch can be adjusted - if you can get your hands and wrenches under there, that is

 

[Robcat]

The hazards do not work. I was planning to look into that after I got everything else working. Guess I'll give it a try now.

I don't think adjusting the switch plunger will make a difference. I used my voltmeter to determine that juice flows to the next stop (gw wire into turn signals) when the pedal is pushed.

I just double checked the ground, and added an extra "just in case" ground wire. Still no brake lights.

 

[Cleg]

A tip on the hazard switch assembly.
In case you are tempted to take the hazard switch apart to clean the contacts be advised that it is VERY DIFFICULT to put back together.
Suggest testing it with an ohmmeter and if it is functional, don't disassemble it.
If you need to take it apart do it in a place that you won't lose any tiny parts when they spring out of the housing.

 

[bj40green]

On your year Cruiser the brake and blinker circuit use the same rear bulb (filament).
In other words: When you make a right turn and at the same time hit the brakes, the left light is steady and the right light blinks.
You have only both brake lights when the turn switch is in neutral position.
Check your turn switch. To make it more complicated; If there is a hazard switch....... see diagram.

I don't know if this diagram is 100% correct for your year but is explains how it works.

Rudi

 

[Healey]

Rudi's schematic shows a fuse for turn and one for brake. It's not a fuse issue is it?

 

[Robcat]

Rudi's schematic shows a fuse for turn and one for brake. It's not a fuse issue is it?

I'm getting power to and through the brake switch, so if my logic minus any electrical knowledge whatsoever is correct, I don't think it could be the fuse. Electrical issues baffle me, so I wouldn't be surprised to find I'm wrong.

 

[Robcat]

The schematics I have seem to show separate flasher relays for turn signals and hazards. Mine only has one...is this correct for a '70? When I turn the hazards on, the flasher gives one click, then nada. If I turn them on while the turn signal is engaged, the flasher lets out a very sad sounding steady buzz, like it's begging for mercy.

 

[bj40green]

The schematics I have seem to show separate flasher relays for turn signals and hazards. Mine only has one...is this correct for a '70? When I turn the hazards on, the flasher gives one click, then nada. If I turn them on while the turn signal is engaged, the flasher lets out a very sad sounding steady buzz, like it's begging for mercy.

Sounds like a ground problem.

Rudi

 

[Robcat]

Does the switch itself ground to the dash? The dash has been resprayed at some point, so if that's where it grounds, I'll need to expose some metal.

 

[bj40green]

Does the switch itself ground to the dash? The dash has been resprayed at some point, so if that's where it grounds, I'll need to expose some metal.

No. The switch carries voltage on all terminals. Check the grounds at the bottom of the turn lights. The mounting bolt(s) needs good contact with bare metal.

Rudi

 

[DSRTRDR]

only one flasher/hazard relay in your year cruiser in the US market

which wiring diagram are you working off of ?

 

[bj40green]

This should be the wiring diagram. FJ40 USA pre 1972.



Rudi

 

[Living in the Past]

only one flasher/hazard relay in your year cruiser in the US market

which wiring diagram are you working off of ?

My 70 model (10/69 production) has two flashers same as my 68 model (9/67 production). Believe it was late in 1970 when it was changed to a single flasher.

If the turn signals are working in the tail lights then I serious doubt a ground is the problem. Same element in the lamp for both brake and turn signal. Th 70 model did not have a warning light on the dash. The wire from brake light switch goes to the turn signal switch. After that the wiring is the same for both turn signal and brake. One works so would the other. My guess your problem is in the turn signal or the wire from the brake light switch to the turn signal switch. That is if your sure your getting power on both sides of the brake switch with the pedal pushed down.

On your hazard lights before I would do anything I would check the fuse that is inline in the wiring harness. Remove the grill and damper in the middle of the cowl to find it.

 

[Living in the Past]

This should be the wiring diagram. FJ40 USA pre 1972.

View attachment 1112449

Rudi

That is a good diagram as it clearly shows a second flasher for the hazards lights. I think it switched to a single flasher earlier than 72. Mark (coolerman) would know best.

That optional flasher was standard in the US market on 68 models and later. Still unsure about earlier if they were standard or a option. The switch had bracket bolted to the bottom of the dash. 68 model had a lower padded dash and the switch was mounted on the face of the dash like the other switches.

 

[Coolerman]

Missed this thread...
If you still don't have this working, then do the following.

Open the hood. On the passenger side firewall there are two 4 pin plugs. These are the plugs for the rear chassis harness. Unplug the two plugs. Now look at the male plugs only as they are the ones that go back to the rear lights. One of the plugs will have both a Green/Yellow and a Green/Orange wire in it. Use a jumper wire to the + terminal of the battery and touch it to the Green/Orange and Green/Yellow wires one at a time. GO is left and GY is right. If they light up, the rear harness, lights, and the ground for the lights, are all good and the problem must be the turn switch or the Hazard switch.