Hand brake light switch photos?

[lobf]

Yeah okay I’m not sure where to go. 
 

I pulled out the back seat to trace these wires and make sure one wasn’t lost somewhere. However even from under my seat it’s a bundle of 3 wires: 2 that plug in to the seat belt buckle, which leaves one for the hand brake. 
 

As mentioned, the wiring diagram appears to

show this light being controlled by a single wire, which I assume should be hot and activate the light when grounded. 
 

Is there a 4th wire I’m missing here? If so, where’s it come from? If not then shouldn’t this orange / green one be hot? 

[lobf]

Bumping this in case anyone has more info ?

[John_in_VA]

The (single) wire for the switch in my '74 runs under the carpet along the driver's side of the tranny tunnel towards the front of the car,

[lobf]

50 minutes ago, John_in_VA said:

The (single) wire for the switch in my '74 runs under the carpet along the driver's side of the tranny tunnel towards the front of the car,

i meant to post this photo before but apparently I didn’t. 
 

I have 3 wires coming from under the back seat, picture here. As mentioned previously, 2 of them to to the seat belt buckle, and one just ends. 
 

I don’t seem to have anything coming from the front of the car along the transmission tunnel on either side. 
 

Also attaching a photo of the wiring diagram I got from here. 2 questions on that: 

 

1) am I reading it correctly that the circuit completes / light comes on when grounded? 
 

2) what is that round thing that the hand brake light goes to? It looks like it ends at terminal 7 or 8- is that my emergency lights button? If so, are the terminals on it numbered, or is there some way to count to it? 
 

thanks! 

 

[Einspritz]

What year is your car?

And what color is the side you hold in your hand with the heat shrink?

The large "round thing" in the diagram is the plug on the back of the gauge cluster. There ARE numbers molded in to identify the circuits.

[lobf]

3 minutes ago, Einspritz said:

What year is your car?

And what color is the side you hold in your hand with the heat shrink?

The large "round thing" in the diagram is the plug on the back of the gauge cluster. There ARE numbers molded in to identify the circuits.

 

It's a '76, the most confusing year apparently. 

 

The color of the wire inside the gray heat shrink is brown and blue. It's also pictured under my back seat there with the 2 wires for the seatbelt alarm. 

 

And copy you, thanks for letting me know. I already have the cluster out since I'm lubricating my speedo cable so that's convenient! I'll see if I can find and trace that wire. 

[PaulTWinterton]

1 hour ago, lobf said:

2) what is that round thing that the hand brake light goes to? It looks like it ends at terminal 7 or 8- is that my emergency lights button? If so, are the terminals on it numbered, or is there some way to count to it? 

 

I'll post this picture again.

 

If memory serves, it looks like it goes into #5 as per your diagram.  I spliced it into my 73 cluster plug for the brake warning light.

 

You are correct in assuming the wire is hot.  It's hot when the ignition is on and the handbrake is active OR if the hydraulic fluid reservoir is low on fluid.

[lobf]

Sorry Paul I guess I didn’t know what I was looking at at the time. 
 

You are correct, it is terminal 5. And look at that, it’s the same blue / brown wire that I find under my back seat that I’m 95% sure goes to the hand brake switch. 
 

I’ll try and trace this and see if I can find anything, but regardless this simply makes no sense to me: 

 

If that wire isn’t hot, and my brake fluid reservoir is full, HOW IS THE HAND BRAKE LIGHT ON?? That makes no sense!! I guess I need to look for an accidental circuit being made somewhere from the brake fluid reservoir too? 

Edited January 22, 2021 by lobf

[Son of Marty]

Under the brake booster support you'll find the brake lines go thru a junction that measures the 2 circuits for pressure differential on the back of that junction you'll find a reset switch press that and see if the light goes off.  Oh also on a square light car that light may indicate low fuel level.

Edited January 22, 2021 by Son of Marty

[lobf]

19 minutes ago, Son of Marty said:

Under the brake booster support you'll find the brake lines go thru a junction that measures the 2 circuits for pressure differential on the back of that junction you'll find a reset switch press that and see if the light goes off.  Oh also on a square light car that light may indicate low fuel level.

I followed the brake lines out from the firewall to the brake booster. They go underneath it but don’t intersect anything, just a straight shot up to the device in the attached photo. 
 

is this what you’re referring to? If so I don’t feel a switch. 

[Son of Marty]

Yup that's the poorly described part I was referring to.

[lobf]

6 minutes ago, Son of Marty said:

Yup that's the poorly described part I was referring to.

copy that, do you know what this part is called? Maybe if I can do some research on it I can figure out where the switch should be 

[Son of Marty]

Brake pressure differential switch, the reset button should be between the 2 wires afaik.

[lobf]

Found it, thank you. 
 

Do you happen to know if this is a button that I press inwards? Or does it go side to side? It seems pretty gunked up and I don’t want to force it 

 

EDIT- it pushes in. 
 

THIS SOLVED IT! You sons of guns, that was the answer. Brake light turns on and off when I ground that blue / brown cable now. 
 

Thank you all so much for your help! 

Edited January 23, 2021 by lobf

[Son of Marty]

Man it's been to long to say for sure, just don't remember.