Brake dummy light

[Subourbon]

I had previously posted about a wanting to remove brake dummy light switch on the proportioning valvebl. But the but that holds that switch to the body of the valve is just seized, won't budge.
Anyways, fast forward through fixes and this n that.

Brake line where leak was that caused the prop valve issue is fixed. I got quick bleed screws in on wheel cylinders, and a vacuum bleeder in the back.

Missus is lumping the brakes as I crack a caliper bleed up forward hoping to recenter properly valve piston. Dummy light is still on. (Missus' break was over so she had to go back to the "office", work from home life is sweet). Anyways im scratching my head what the hell... the master cylinder level went down for the rear! Huh?!

Run to the back open up a quick bleed and apply a bit of vacuum with the bleeder. I'm getting fluid! What on earth!?!
After doing this on both wheels cylinders and a bit of pumping, she's a hard pedal now folks.

But!
The dummy light is still on!

I was out there today having a look around the valve:
Now, i know that normal operating mode a pin sits inside the valve floating above the part of the plunger (piston) that is tapered so its not making any contact. Circuit open, no dummy light.

Now should you lose fluid front or rear, depending, the larger diameter of piston makes contact with the pin, pushing it up to the switch, closing the circuit and triggers the light.

I thought, maybe its stuck up, so with a pick i tried pushing it down but she's stiff, feels like im making contact with something... I took a picture of the pin, (bear with me folks its in the stock position under the rad support, so it a pics through a telescopic mirror that I angled to see)...

But when i was researching this after coming inside before posting here, the pins in the images on the google machine looked just like mine here.

So after all that history and context, here are my questions:

Could a bad ground trigger this warning light?

I haven't really gone for a drive yet coz I have the dash torn apart in preparation to install dakota digital and I want to make sure everything works before I start using the wires from the 18 pin plugs to the old cluster,
but reason for saying this is, maybe the pedal needs more pumping from a regular Drive, maybe plunger is only slightly reset?

Reason why I think could be bad grounds also is:

The signal wire isn't connected at the moment, its as it is in the picture below, meaning circuit is open, so no light. But the light still there!

So, is it possessed, am I not understanding this part of the system electrically?!
Id love some help with this, its so weird.

 

[Ricko1966]

Check the switch on the parking brake

 

[Goldie Driver]

Not sure to answer you, but any chance the parking brake is on?

That will turn on a brake light.

Britt

 

[Subourbon]

I did check the parking brake, I pulled the release, and nothing. Now, like I said my dash n interior is torn apart, and the ground down by the left knee under the dash there was a ground wire there that was disconnected. And I didn't do that. I reconnected it.
Is it possible the electrical circuit for the mechanical e brake is just fried and by reconnecting that ground its causing the issue? Or am I reaching too far?!

 

[Brad_B]

I just went through this while installing NVU gauges. I had to take the parking brake off “switch” off and clean it all up. Once I did that it was all good. Not sure on the Dakota gauges, but the brake light is a ground trigger and I had to wire in a relay to get it to work correctly. Once the switch was clean and relay wired correctly, works great. The switch is hard to reach but doable to remove especially with the seat out. Good luck.

 

[Subourbon]

I just installed ths box for the vhx dakota digitals. I believe theres just a 1 wire connection going into the box. I jist wanna clear any lights before making the final switch over.

Ill check out the e brake tomorrow. It'd be weird if thats the case, I don't use it.

Thanks for the tips guys.

Can any of you speak to the position of my the pin on the prop valve. Is it high, as in triggered, or normal position?

 

[Subourbon]

I found the wire, tan with white tracer.
It was connected to a ground.
Parking brake isnt engaged but appreciate you guys mentioning it. Kinda helped zero in on the issue.
Now prop valve is disconnected so is the parking brake. Light is off.

So now, I can confirm if prop valve is fully reset by reconnecting and verifying the light stays off.

Then try n reach back there and hook up tan wire with white tracer to parking brake.

If anyone stumbles on this and wonders wtf were on about, this post really narrowed it down too

https://www.gmsquarebody.com/threads/brake-light-stuck-on.10478/#post-939858

Post number 8 chengny, with that pic, what a save!

Cheers all!

 

[Subourbon]

Yeah just stuck my phone with light on down under there. The male end of spade connector has left the chat.
Who knows when probably since before I was the owner lol. I think i can live without it. Never used the parking brake once. Like insaid when I took apart the dash n tried identifying what everything is i just saw this wire and assumed it was a ground. Whoops.

Prop valve is all reconnected. No more light. Crisis averted.
Maybe I'll look into getting another switch just to have everything working nicely. But for now, im pretty pleased.

Thanks again for the feedback n answers guys, always learning!