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Getting solid brake light on cluster. E-brake not applied, and brake fluid level is full. I want to test brake fluid level sensor can anyone tell me how? The service manual says pins 2 and 3. Pins 2 and 3 both have continuity on the connector and sensor sides. I am not sure what to do next to confirm sensor is good or bad
Since your reservoir is full, the “most likely” (for this gen) culprit is a failing solder connection on the gauge closer circuit board. If you search around here, you’ll find many threads on it. Include searches for “shim” or “shimming” the plug. And/or if yoh take it apart and wiggle the plug, you may find that dash light goes on and off as you wiggle / shim.
having been through this, here is my recommendation:
- suggest living with it as long as you can
OR
when/if you can’t live with it, I would just get gauge cluster replacement or repair done when you pull it apart.
in my experience the “shim” fix is only a temporary fix, and may not work at all.
good luck and update thread with your findings/solutions.
Since your reservoir is full, the “most likely” (for this gen) culprit is a failing solder connection on the gauge closer circuit board. If you search around here, you’ll find many threads on it. Include searches for “shim” or “shimming” the plug. And/or if yoh take it apart and wiggle the plug, you may find that dash light goes on and off as you wiggle / shim.
having been through this, here is my recommendation:
- suggest living with it as long as you can
OR
when/if you can’t live with it, I would just get gauge cluster replacement or repair done when you pull it apart.
in my experience the “shim” fix is only a temporary fix, and may not work at all.
good luck and update thread with your findings/solutions.
Had a friend reflow all the solder joints on the cluster circuit board. My check engine light was not illuminating as well as my airbag light so I got the 5x5 chimes every 30min. Airbag and check engine light working properly now no more chimes. Brake light used to blink when I fiddled with connector but now stays on, why I want to test level sensor. Also looking into testing parking brake sensor. Just want to confirm both working properly and rule them out.
Last edited by Boston 04 F150; Jan 23, 2024 at 01:51 PM.
Had a friend reflow all the solder joints on the cluster circuit board. My check engine light was not illuminating as well as my airbag light so I got the 5x5 chimes every 30min. Airbag and check engine light working properly now no more chimes. Brake light used to blink when I fiddled with connector but now stays on, why I want to test level sensor. Also looking into testing parking brake sensor. Just want to confirm both working properly and rule them out.
understand; but sounds like before friend did solder work the only problem (with brake light circuit) was the connector/connection. If it wasn’t the only problem; then fiddling with it wouldn’t have resulted in light (temporarily/intermittently) going on/off. Seems like it would be a ‘major’ coincidence if his solder work simultaneously fixed the connector problem AND compromised the brake fluid or pedal sensor.
Park brake head sensor is just 1 wire that grounds and turns on the red brake light
Those master cylinder level sensors fail
Replace the reservoir or just the sensor if it unplugs from the reservoir
I think the solder issue is few and far between, meaning they don't all do it
I have fixed several GM instrument clusters resoldering (and replacing) LEDs.
Problem is not on all their clusters either
I've seen so many faulty level sensors, I give it Frank Zappa odds 50-50
The level sensors used to be about 12 bucks and slide out of the bottom of the reservoir
Yours may need a new reservoir if it's not that slide out style
Park brake head sensor is just 1 wire that grounds and turns on the red brake light
Those master cylinder level sensors fail
Replace the reservoir or just the sensor if it unplugs from the reservoir
I think the solder issue is few and far between, meaning they don't all do it
I have fixed several GM instrument clusters resoldering (and replacing) LEDs.
Problem is not on all their clusters either
I've seen so many faulty level sensors, I give it Frank Zappa odds 50-50
The level sensors used to be about 12 bucks and slide out of the bottom of the reservoir
Yours may need a new reservoir if it's not that slide out style
I’ll check if I have the slide out type sensor. If part only $12 then it’s worth replacing just to rule it out in my opinion. Still planning to test parking brake also will report results
could also be the parking brake not releasing all the way. looks like that truck has some corrosion.
That’s a good point I’ll look into that when I test park brake sensor. Truck definitely has corrosion and rust. Here in New England winters are brutal on vehicles the salt rusts everything. Overall my F150 is holding up relatively well considering it’s 20yrs old. Hoping to get a few more years out of it
How to test brake fluid sensor?
