Why is this on dimly?

Discussion in 'Small Block Tech' started by Mark Demko, Oct 17, 2021.

  1. Mark Demko

    Mark Demko Well-Known Member

    06EE6D22-9A1C-4999-AE2E-16ECF5A51B83.jpeg Put led lamps in, all works/looks good. but now my “brake” light is dimly lit:rolleyes:
    Something simple I’m sure.
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Check the parking brake switch.
     
    Briz and Mark Demko like this.
  3. TrunkMonkey

    TrunkMonkey Well-Known Member

    Had that happen on my '68 when I put LED bulbs in the dash.

    Figured it has something to do with the variable voltage for the "high/low" illumination for the Parking Brake/pressure switch, I believe there is very low voltage on the circuit for the pressure switch, and may be enough to illuminate the LED, I put the incandescent back in.
    (I did not feel like playing "chase the electrons")

    One peanut bulb is not gonna suck all the juice outta my battery, and I am pretty sure the 140 amp alternator will keep up. It might run a thousand degrees hotter, but I'll just drive faster to keep good airflow.
     
    Last edited: Oct 17, 2021
    Max Damage and Mark Demko like this.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Mike,

    Pretty sure Mark left all the indicator bulbs incandescent. That brake light is not an LED.
     
    Mark Demko likes this.
  5. TrunkMonkey

    TrunkMonkey Well-Known Member

    OK.
    I read this and thought he meant he put LEDs in the dash. :)

    "Put led lamps in, all works/looks good. but now my “brake” light is dimly lit"



    Just in case anyone has a similar problem.

    In my '68, I did have trouble for a while getting my valve to stay centered.

    It would flicker and come on while driving, but as soon as I lightly touched the pedal, it would go out. If I stepped hard, it would come on. I did bleed several times (using the centering tool), and finally bought "Russell check ball bleeder screws" and bled it again, still did it, and then after about 2 weeks if driving, it stopped. (I did meter the pressure switch and also checked the Parking brake switch and they do work, so I am not sure what it was, maybe enough air that finally moved out of the valve/body).

    But the LED install was after all of that (and I though the problem "came back"), changed the bulb and it was fine again.
     
  6. Mark Demko

    Mark Demko Well-Known Member

    Yes, Larry is correct, incandescent bulbs are still in the “indicator “ positions, I may have jostled something when I lowered the column to pull the cluster forward, damn I HATE the thought of having to remove dash pad, cluster and appendages, old plastic is only tolerant for so long:mad:
     
    Waterboy likes this.
  7. Mart

    Mart Gold level member

    Yep.
     
    Mark Demko and TrunkMonkey like this.
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Then, remove the lower dash plate, and drop the column down. Play with the wiring and see if you can spot the problem.
     
    Smartin and Mark Demko like this.
  9. Mark Demko

    Mark Demko Well-Known Member

    Yep, gonna try the simple stuff first.
    Just put gas in it and took it around for a drive, all functions normal, so its something simple;)
     
  10. Mart

    Mart Gold level member

    Yep, simple.
    Like those led's not being totally compatible in our old bucket of bolts 50 yr old cars.:D:D:D
     
    Mark Demko likes this.
  11. Mark Demko

    Mark Demko Well-Known Member

    LOL the '71 Buicks are late model compared to the 70's and earlier:p:p:p
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Pot stirrer.:D:D:D
     
    FLGS400, Mart and Mark Demko like this.
  13. TrunkMonkey

    TrunkMonkey Well-Known Member

    Try unplugging your car and plugging it back in.
     
    Ken Mild, BUICKRAT, BYoung and 4 others like this.
  14. Bens99gtp

    Bens99gtp Well-Known Member

    Ah hell you dont need that light, you will know if you have a brake issue, do you really need a light to tell you.......lol
     
    Mark Demko, Mart and Fox's Den like this.
  15. Mark Demko

    Mark Demko Well-Known Member

    Yah mean clear the code?:p:p:p:p:p
     
  16. TrunkMonkey

    TrunkMonkey Well-Known Member

  17. Mark Demko

    Mark Demko Well-Known Member

    Lol that was a good movie:p
     
    TrunkMonkey likes this.
  18. Lane in Mt.Hermon

    Lane in Mt.Hermon Well-Known Member

    I hope this isn't too dumb or off the charts relative to this thread but earlier this year when I switched my park lights and front turn signals to utilize the same LED bulb [double filament version] I had problems. American Autowire tech support suggested I change to an LED Flasher Can that will operate with both LED and incandescent bulbs [PN 510226]. I did and the problem went away. I was using their wiring harness for the whole build. This was on my '46 chevy truck [with Buick 350 v8 and matching TH400]. The old [and I mean old] taillights that I completely rebuilt from the inside out stayed incandescent. I wanted to keep and use the old taillights and was unaware of the two bulb types being incompatible with some flasher cans. The reason for doubling up the park light and front blinker is that the headlight buckets on a '46 have only the park lights ...... as a turn signal in those days would have been an add-on to the top of the fat fender.
     
  19. Mark Demko

    Mark Demko Well-Known Member

    29911E78-D156-484B-800C-F4B00DB6DA5B.jpeg
    We’ll you we’re pretty much correct, I removed the left cluster and removed the socket for the “BRAKE” light, WTH, I put an LED in there:rolleyes:
    I did not remove the clusters when I put the LED’s in, and for some reason, being there’s 3 gauges in the left cluster, I put 3 LEDs in:p
    Put a regular bulb back In and my GS runs 12.40 now:p:p:p:p
    It’s weird tho, where was the LED getting its current from to illuminate????
     
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    It doesn't take much current to illuminate an LED. It probably back fed from somewhere. Sought of like the MSD run on that is solved with a diode. Current back feeds through the regulator and GEN light and keeps the MSD box energized on. Again, it doesn't take much current to keep the MSD box on.
     
    Mark Demko likes this.

Share This Page