Brake Warning Light illuminated '83 Fj40 (1 Viewer)

[Jim S.]

The 2 leads from the Master cylinder reservoir are not connected to anything. There is a female connector on the wiring harness available and I have jumped the reservoir leads to it with no success. I have verified the parking brake connection. I don't have a wiring diagram and need help sorting this out. Will also need to source the connectors. Thanks.

 

[firemanj92]

@Coolerman ?

 

[JohnnyC]

Here’s your wiring diagram:

http://www.globalsoftware-inc.com/coolerman/fj40/schematics/FJ40/1983FJ40/36679A%20Wiring%20Diagram%201983%20Pickup,%20LC40,%20LC60.pdf

 

[Jim S.]

Much appreciated

JohnnyC​

 

[ToyotaMatt]

The 2 leads from the Master cylinder reservoir are not connected to anything. There is a female connector on the wiring harness available and I have jumped the reservoir leads to it with no success. I have verified the parking brake connection. I don't have a wiring diagram and need help sorting this out. Will also need to source the connectors. Thanks.

View attachment 3224852

View attachment 3224855

maybe the correct OEM Cap , is place of the aftermarket one there is something to consider if @Coolerman cant assit you ?


let me know if i can help

thanks

 

[Living in the Past]

I'm curious Jim is everything else on the brake light system working? With a diode in the brake light circuit appears the brake light should be on once the key is turned on and the engine isn't running. That is with the hand brake pulled or not pulled. The Hanyes manual for the 81/82 shows a resistor right next to low level switch in the circuit. Not sure it's purpose. Since the cap used is the same 8/80-10/84 guessing 83 has that resistor as well. Interesting the wire colors changed between 81 and 82. Wouldn't guess what color 83 has. To trouble shoot the wires from the harness with ignition switch off both wires should be ground. Switch on one wire should be positive. That's assuming the purpose of the diode is to show the brake light lamp itself is working.

 

[Engineer8000]

That brake light on the later trucks doubles as a alternator idiot light, hence the diode and connection to the Y alternator wire. Each path provides a ground to the light.

The light should come on if e brake is pulled, low fluid level or key on, not running (alternator).

I have this arrangement in my 73 (not original). The brake light will ghost in at idle. Adding a charge light relay to stop that.

 

[Jim S.]

Folks I'm still chasing this but not working on it as much as I would like. Unheated garage with morning temps in the low 20s. Mid afternoon temps are doable. I suspect the diode associated with the internal voltage regulator / alternator might be the issue. Is the diode in the alternator or at the end of the yellow wire? I'm also attempting to remove the dash. I have all knobs off except the warm pull and fresh air pull. I loosened the nut behind the fresh air pull but I'm not getting anywhere. Want to replace the bulbs in the warning annunciator and make certain all the wiring is squared away. Thanks for all the assistance.

 

[Engineer8000]

Not sure about the diode location. They are usually wrapped up in the harness, hard to find. I would definitely do some voltage and continuity checks before going after that.

 

[Jim S.]

I'm Getting .8V across the light.