[Fixed!] Brake Telltale Randomly Turning On and Off

After replacing my brake pads last week and bleeding the entire system I sustained a slight brake fluid leak from my driver rear wheel. Yesterday I tightened the bleeder screw to stop the leak. This morning I took the truck out and now my Brake telltale randomly turns on and off. I verified the master cylinder is full of clean brake fluid (maybe very slightly overfilled though). I'm pretty sure it's not the switch on the E-brake handle, and I don't notice anything unusual when I brake.

Any thoughts as to what the problem might be?

 

What is a brake telltale?

 

If you push the parking brake handle in does the light go out??

The spring at the intermediate Lever(in front of the fuel tank) sometimes needs lubed about every oil change .

That spring keeps tension on the cable and pulls it against the switch.

Another possible thing is a loose connection from the switch on the master cylinder cap

 

A "telltale" light is a light that turns on to "tell a tale" about a given circuit. For example, the Oil Pressure telltale turns on to tell you something is wrong with the oil pressure. (old-school term, I know.)

I didn't do anything inside the cab when I replaced my pads except pump the brake pedal when I bled the brakes. I don't think that I have a loose connection at the master cylinder, but it's probably something in that area. Could be that I overfilled the reservoir.

I just now removed the cap, sucked out some fluid from the MC and then carefully topped it off, this time being careful not to overfill it. The inside of the reservoir is stained brown, so I had to shine a light behind the MC to see exactly where the fluid level was. The new fluid is kinda hard to see when it's inside an old reservoir. We'll see when I take the truck out again. If the problem is still there, then I'll recheck the connection. Whatever the problem is, it must be around the MC. Thank you for your suggestions!

 

@skeezix Brake fluid containg water will stain the MC reservoir.
Brown plastic is a telltale.
MIL is Malfunction indicator light.
You can have a CEL with or without a MIL

 

Sometimes if the front cable is starting to fray but the tends to be all the time not intermittent

 

MIL = CEL ..MIL is just the industry term, and I think OP was right about what a “tell-tale” is, definitely an older term I’ve never heard.

https://en.m.wikipedia.org/wiki/Tell-tale_(automotive)

learn something new every day..

 

OP, electrically speaking there's only two things that turn on the brake idiot light:

Both of these circuits pictured above are ground switched, meaning the switch that "closes" the loop is on the ground side of the dash not the positive side. That being said if you look at the screenshot of the FSM it's just the parking brake switch and the brake fluid level switch. If you've physically checked the brake fluid level and confirmed that the spring and cable are lubed/free like @Wyoming09 said...then my only advice would be to test those two switches. The parking brake switch is easy to test, you can just put a multimeter across it (one pin to the + side and the other to the - side or a ground point) and test continuity/resistance while cycling the switch. As for the brake fluid level switch I'm gonna have to do a bit more research on how to test that because it isn't just a simple switch, and I didn't see anything in the FSM but I'll look again.

EDIT:
I'm dumb, I just didn't scroll far enough down in the manual. Here's the troubleshooting for the brake light:

 

I drove the truck yesterday and the Brake telltale never came on. That's odd because if anything, I had too much fluid in the MC.

I really appreciate the added info that Goldentaco03 provided in his edit!

 

So what was the fix?
Jiggle the connections?

 

I have not the foggiest idea what I did to fix the problem. Short-term memory is shot

I can say that I didn't touch the under-dash switch, nor did I lube any cabling.