Electrical help- blinkers and brake lights...

[SouthBostonFJ]

Can anyone come up with a good reason why when I depress the brake pedal, my rear right brake light and my front left blinker light come on? I know the PO screwed around with the wiring when he replaced the signal arm on the column. All of the other lights work perfectly. I believe when he plugged in the wires from the new signal arm switch, he did it incorrectly. Is the brake pedal switch tied into the signal switch somewhere?

[Coolerman]

Yes, the brake light switch is part of the turn signal wiring. The ONLY way to see this is to look at a schematic and start tracing the wires.

Before doing ANYTHING: Insure that ALL your light housings are grounded properly, the bulb sockets are free of corrosion, the bulbs are actually good, and your flasher is good.

Then find the wiring harness coming from the turn signal and using a schematic ensure that the wires are connected correctly to the main harness. There a 6 wires with bullet connectors and they must go to the correct bullet connectors on the main harness.


This may help... It shows how the Hazard flashers contibute to this mess. See my web site, I cover a lot of turn signal stuff...

[Pin_Head]

It is a "floating ground" or ground loop problem.

One (or more) of the rear lamp housings has a bad ground, so power flows through the turn signal filament until it finds a good ground in the front housing. Clean the lamp housing-frame contact or install a ground wire from the lamp housing to the frame and the problem will go away.

[SouthBostonFJ]

The housings are all rust free and the grounds and bulbs are good. Everything, including the hazard lights, work as they should. That's why I think a wire must be plugged into the wrong connector.

[SouthBostonFJ]

Coolerman,
I borrowed this picture from your site. I need to know if one of these contacts is inserted into the wrong connector, could it cause my problem?

[Vicm]

Change your left brake bulb with a good one.

[Coolerman]

Yes I can see how having the wrong wire plugged to the wrong place could cause this. The wires are color coded, and should match across the bullet connectors... There are two Green/Orange (front left and rear left turn) and two Green/Yellow (front right and rear right turn) wires. Then a Green/White which goes to the brake light switch and a Green/Blue that goes to an inline fuse then to the Hazard switch. Double check the colors match across the bullet connectors.

[SouthBostonFJ]

Thanks guys, I'll look at the connections and the bulb.

[Fast Eddy]

Originally Posted by Coolerman

This may help... It shows how the Hazard flashers contibute to this mess. See my web site, I cover a lot of turn signal stuff...

Great picture. I have the whole diagram, but I never noticed this part of the wiring.

On my rig, when I pull the flasher knob out I lose blinkers for 'a while'. They come back later.

I want to debug it to get it working, and I plan to use a flasher switch and a blinker circuit in my e-locker wiring, so I want to understand how those parts work better.

[Coolerman]

I cannot take credit for that pic, I believe it came from possibly the FAQ's or the archives. Who ever figured it out, my hats off to them!

I found it invaluable when trying to figure out the hazrard switch...

[Kroll]

I recently upgraded my round lights to the rectangular ones on my 72 FJ40.
remember that the older cruisers have only 2 wires going to the rear lights from the front.
One wire does running lights and the other turn signals/brakes.

[Hugh Heifer]

Originally Posted by Kroll

I recently upgraded my round lights to the rectangular ones on my 72 FJ40.
remember that the older cruisers have only 2 wires going to the rear lights from the front.
One wire does running lights and the other turn signals/brakes.

I want to maintain my single light in the rear on my 72 but up grade to a later model steering shaft and collar. Can't seem to find the thread on it but I know it is here someplace.