Results 1 to 7 of 7

Thread: Brake lights not lighting up at full brightness

  1. #1
    Senior Member Gregadeth's Avatar
    Join Date:  Jun 2011

    Location:  Los Angeles, CA

    Posts:    338

    My VIN:    6472

    Brake lights not lighting up at full brightness

    I noticed recently that although my brake lights work, most of the time they don't light up as bright as they should (see pic 1). They're about as bright as the tail lights when those are on. Sometimes after a few presses of the brake pedal, they'll light up fully bright (see pic 2), but then when I press it again, they light up dim. This seems to me like a connection issue somewhere, because it's intermittent. I replaced all the bulbs with LEDs a couple of years ago, and just noticed this issue recently. Has anyone had this same issue and could direct me where to check first?

    VideoCapture_20180807-020607.jpgVideoCapture_20180807-020618.jpg

  2. #2
    Senior Member DMC5180's Avatar
    Join Date:  May 2011

    Location:  Reedsburg, WI

    Posts:    3,738

    My VIN:    5180

    Club(s):   (DMWC) (DCUK)

    The exterior lighting is divided into left and right fused circuits. Since this appears equal on both sides, I Would look at the common points in the feed circuit. Brake light switch and connections too it. Would be my first place to look at. Tarnished internal contacts can cause funny things like that.


    Sent from my iPhone using Tapatalk
    DENNIS

    VIN 5180, Frame 3652, STAGE I, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID sealed beam style headlights, SPAX user since 2009, Eibach springs, Mid-State Club Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, GENUINE MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

  3. #3
    Administrator Ron's Avatar
    Join Date:  Jun 2011

    Location:  North GA

    Posts:    4,532

    Club(s):   (SEDOC) (DCUK)

    The brake lights are all on fuse #18. Check/clean the connections there and the Black Bulkhead connector #41 (Green/Purple wire = Stop Lights). Here, #35 supplies ground for both boards.
    StopLights.jpg

    There are different version of how the switch itself is wired in the footwell. If the connections to it are ok, suspect the switch itself.

  4. #4
    Senior Member DMC5180's Avatar
    Join Date:  May 2011

    Location:  Reedsburg, WI

    Posts:    3,738

    My VIN:    5180

    Club(s):   (DMWC) (DCUK)

    Not all cars used Fuse 18. Mine is empty no terminals. Iíve never figured out if the use of fuse 18 was only on early VINs that was later eliminated or vice versa.


    Sent from my iPhone using Tapatalk
    DENNIS

    VIN 5180, Frame 3652, STAGE I, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID sealed beam style headlights, SPAX user since 2009, Eibach springs, Mid-State Club Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, GENUINE MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

  5. #5
    Administrator Ron's Avatar
    Join Date:  Jun 2011

    Location:  North GA

    Posts:    4,532

    Club(s):   (SEDOC) (DCUK)

    +1

    If fuse #18 is not used, there will be a an inline fuse down by the switch.

    fwiw, I have found a few of the inline fuses to be the cause of no brake lights (not intermittent) while not appearing to be blown.

  6. #6
    Senior Member aipri's Avatar
    Join Date:  Jul 2013

    Location:  Southern NJ

    Posts:    159

    My VIN:    16823

    Club(s):   (DMA)

    Not sure if this is the same issue or not, but I had a problem recently where my brake lights would sometimes be dim or not turn on at all. It turned out to be the little switch under the brake pedal that gets depressed when you press the brake pedal, not sure the official name, but DMC sell them. I replaced it and the brake lights were back to normal.
    Anthony

    1983 DMC-12 VIN 16823
    2014 BMW M5

  7. #7
    Senior Member Gregadeth's Avatar
    Join Date:  Jun 2011

    Location:  Los Angeles, CA

    Posts:    338

    My VIN:    6472

    Thanks for the suggestions

    I took the advice to focus on the brake light switch. First I bypassed the switch by removing the two wires and connecting them with a fuse. This made the lights come on nice and bright. The connectors looked good as well, which left only the switch itself as the culprit. I made a mental note to order a new switch, but then I got an idea. I grabbed a small hammer and gave the switch a few light taps and guess what, it fixed it! It's been a few days now and I've tested the brakes countless times, and it's been 100%. Gotta love an easy fix. I'll continue keeping an eye on it, just to be on the safe side. I'd advise others to check their brake lights as well. Your lights may be turning on, but they may not be at their full brightness, which in turn becomes a safety issue.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •