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Parking brake light again....

Discussion in '80-Series Tech' started by davidfj406080, May 4, 2003.

  1. davidfj406080

    davidfj406080

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    ??? Well I finally troubleshot the parking brake light today after it came on constant. It has been intermittently illuminating very dim, mostly noticeable at night. Being an eternal pessimist I was hoping for the worst-
    I called Beowulf and he reminded me of the answers to my post last month- so I disconnected the plug to the brake fluid reservoir and the light went out. Then I took out the level sensor and cleaned it in denatured alcohol, and put silicone grease on the rubber parts. Reinstalled and it acted like before-
    I then adjusted the parking brake and discovered yes, they are two different switches-
    SO, it looks like I need a new brake fluid level sensor switch, right? I don't have a real manual for an 80 series, just a Haynes so I can't check electrical switches. I don't want to buy something I do not need as I have a garage full of FJ40 and 60 miscellaneous parts! Any guidance will be appreciated-
     
  2. landtank

    landtank SILVER Star

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    Yes the fluid level switch is what you need. As far as the wiring goes it is quite simple. 12vdc is supplied at one side of the bulb in the dash, the other side of the bulb (-) then branches out and goes to the fluid level switch and the e-brake hand lever switch. Those switches are attached to ground so if either or both of those switches are triggered then the light comes on. In your case the fluid switch has most likely gotten contaminated where some connection to ground has been made but not a good one so the light only comes on occasionally or very dim.
     
  3. Scamper

    Scamper

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    I don't know the history of what your problem is/was, but i have found that as your pads wear (get towards the end of life) that your fluid level can drop sufficiently to make the brake light behave as you've said. Have you added a bit of fluid to see if the problem goes away? If so, it's not your switch, just the fluid level.

    Tom
     
  4. davidfj406080

    davidfj406080

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    Landtank, Scamper- thanks for the replies- yes, I topped off the reservoir first, but topped it off about a month ago, too- haven't been able to check out the brake pads yet but I will do them/ knuckles real soon. The fluid level sensor makes sense; when I inspected it it looked like it was the wiring was potted in at the top with some sort of compound that was deteriorating so I JB welded it and there was no change. My hunch is the sensor was fouled internally after leaking from the top-