Hello everyone,

Long time lurker, first time poster. My truck is a 1994 Pickup extra cab DX 4x4 3.0 with an auto trans. I recently began having trouble with the braking system. I'm hoping someone on here can lead me in the right direction.

These three things started to happen simultaneously within the last week:

- Brake lamps do not illuminate when brake pedal is depressed (3rd brake light DOES illuminate) Running lights work fine.
- Slight gear noise (almost like a fast tick noise) and squeak comes from the gear selector area only when brake pedal is depressed. When i let off, it stops. (trans seems to shift fine and seems okay otherwise)
- The dash brake light comes on randomly while driving then goes off on own.

Here is what I've checked so far:

-Brake switch. (Ruled out: 3rd brake light is working, cruise control is disengaged by pressing brake.)
-Brake Fluid. (Ruled out: full)
-Fuses (Ruled out: puled and replaced same fuses, spread fuse prongs, used a jump wire)
-Bulbs (Ruled out: both filaments intact)
-Bulb connectors (Ruled out: receiving power)
-Examined vac system for leaks. (Ruled out: no cracks observed)

Are the transmission and braking system somehow related? Via vacuum or electrical or something?

The brakes work perfectly, pads and shoes were also recently replaced so the truck stops fine. Its just the electrical and trans issue noted above.

This one has me truly stumped and I've been searching far and wide for the solution.

Any input would be greatly appreciated. THANKS

 

your issues with brake lights not working and your warning light could be related and likely caused by poor grounds. The funny noise is not likely related. need more information, maybe a bad u-joint?

 

So I'm assuming you have volt-meter / multi-meter?
Then, like akwheeler says ^^^ you need ground to your main brake light.

Typically, the brake light is an 1157 dual-filament light. Both filaments share same ground. Lower power filament is the red tail light. Does that work?

 

How can a good bulb NOT light when receiving power?

As akwheeler and Rad4Runner have suggested, I suspect an open GROUND in your taillight. Start by trying to see if you get voltage to the bulb socket by measuring from the inside to outside of the socket (tricky to do). I'm going to guess you measured from the inside to some convenient ground point, which confirms the +12v but does not confirm the ground.

An intermittent brake panel light, as you found, is usually brake fluid. But it could be an intermittent fluid-level switch, or a wonky parking brake switch.

 

Thank you for the responses,

The socket is receiving power (verified with multimeter and by the fact that the running light filimant is working.)

Pressing the brake pedal only illuminates the 3rd brake light and neither of the two lower taillight brake lights. This leads me to believe it is not the brake switch either.

Im not sure its a ground because it is all recieving power, there is just a disconnect between the brake padal and the two lower brake lights.. hmm...

As for the u-joints, ill have to give them a shake this evening. Thanks for the Idea Akwheeler.

 

How sure are you that the bulbs are good?

The EXPERTS^^^ are puzzled why a bulb that is good and is getting power is not lighting up.
How could you say that the bulb is getting power but disconnected from the brake switch?
You could help us help you if you helped us see exactly what you have in front of you.
A PICTURE PAINTS A THOUSAND WORDS.
Like I mentioned above ^^^ you have TWO FILAMENTS on the 1157 bulb. There should be 3 terminals on the socket:
1) Positive for brake light filament.
2) Positive for running light
3) Ground - usually white wire with black stripe.
Exactly where are you probing? Where do you put your positive test probe? Your negative test probe?

 

Welp, I feel like an idiot. Upon further inspection of the bulbs i noticed that the filament was ever so slightly broken. ON BOTH BULBS.

replaced both. Good to go.

Thanks everyone.

 

Thanks for the report.

Like with a good mystery novel, we always want to find out if, after all, "the butler did it."

 

Tnx for reporting back.
Like I always say, our senses (sight this time) are the most important diagnostic tool, followed by the multi-meter. The MM narrowed it down, Sense of sight pinpointed it.

The devil made him do it.