Author Topic: Brake light dimly illuminated  (Read 1937 times)

Tinkerr

  • Member
  • ***
  • Posts: 336
    • View Profile
Brake light dimly illuminated
« on: June 26, 2021, 01:49:29 AM »
Car is a 68 power drum car. The brake components are new or rebuilt. I unplugged the connector on the E brake that made no difference. If I unplug the connector on the distribution block the light goes out indicating a brake issue, but the brakes appear to work with a good pedal. I have fluid at all wheels and I able to bleed all wheels. If I use a test light and use the switch on the distribution block for a ground the the test light will not illuminate. Any ideas?

uscrichter

  • Member
  • ***
  • Posts: 254
    • View Profile
Re: Brake light dimly illuminated
« Reply #1 on: June 26, 2021, 10:39:27 PM »
Most likely a poor ground

Tinkerr

  • Member
  • ***
  • Posts: 336
    • View Profile
Re: Brake light dimly illuminated
« Reply #2 on: June 27, 2021, 02:49:00 AM »
Does anyone know where I can purchase the Brake light switch in the distribution block? I can purchase the entire unit ,but can't find just the switch. The plastic insulator sleeve on mine is broken in half. 

169INDY

  • Hero Member
  • *****
  • Posts: 1373
    • View Profile
Re: Brake light dimly illuminated
« Reply #3 on: June 28, 2021, 06:07:56 PM »
"If I use a test light and use the switch on the distribution block for a ground the the test light will not illuminate. Any ideas? "

That is because when you use a grounded test light to test a ground there is No source of 12VDC positive to illuminate the light. (wrong tool)

Take a VOM (Volt Ohm Meter) on the "Ohms" setting and hook leads as such:
Either: Ground on Body
Other: Attached to the Center pin of the distribution block pin.

Indication/Meaning: Open or infinite; the distribution block differential piston is properly centered.

Indication/Meaning: Shorted or less than infinite; the distribution block differential piston is NOT properly centered, contact made either indicating a loss of even pressure between the front and rear hydraulic circuits at some point in the brake systems history. Investigation is required into the event or defect in the system. Often the piston will need to be manually re-centered. There is a section in the GM Chassis service manual which describes this process.
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

Tinkerr

  • Member
  • ***
  • Posts: 336
    • View Profile
Re: Brake light dimly illuminated
« Reply #4 on: June 28, 2021, 11:38:06 PM »
 I haven't been able to source a new sensor/switch. My dist. block was supposed to have been rebuilt, but upon further testing I think all they did was clean and paint it. I ordered a repo block today.

I could have done a better job of articulating my testing procedure . I was pulling 12v+ from the battery and grounding to the terminal on the block. Thanks for the reply

169INDY

  • Hero Member
  • *****
  • Posts: 1373
    • View Profile
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

Tinkerr

  • Member
  • ***
  • Posts: 336
    • View Profile
Re: Brake light dimly illuminated
« Reply #6 on: July 03, 2021, 03:29:50 AM »
Update: I took parts from the sensor in the repo block and used it to rebuild the original sensor that solved the light issue. The original sensor was missing a small o-ring, the plastic insulator was broken in half and the flat portion was smashed. These issues together allowed the sensor to sit deeper in the block making slight contact creating a light ground. The ground was not strong enough to light my test light, but would dimly illuminate the led light in the dash. 
« Last Edit: July 03, 2021, 03:58:00 AM by Tinkerr »

 

anything