Third Brake Light Electrical Issue

[FloridaCruiser22]

The third brake light on my 80 has been out for...........3 years now. I decided to try to diagnose it a month ago and was stumped, so now I'm here a month later. Procrastination

This is what I've checked so far and I am confused about which direction to go next -

- With the key off --> third brake light comes on
- Pressed the brake pedal --> connector is receiving 9 volts
- With the key on --> third brake light is off
- Pressed the brake pedal --> connector is receiving 3 volts
- Checked the ground wires to the taillights and they look fine

The only thing I can think of is there's a hidden wiring issue/breakage that I'll have to trace backwards. Any suggestions or someone who's dealt with something similar?

 

[Kernal]

Search is your friend

Not an electron guru but assuming you don't have a broken wire going to the third brake lamp, search this forum for ZENER DIODE

(Did it for you)

K

Thread 'Third Brake Light Not Working on 1996'

Feb 29, 2012

My third brake light is not working right now. When I went in for vehicle inspection today, I failed because my brake light was not working. When I checked it, it was working again. I just checked and it is not working, again. What gives? I did a search but no one tells how to actually fix the problem.

Can anyone give me instructions on what to do to get this working again so I can get this REJECTION sticker off my truck? Thanks!

• kino1161
• Replies: 52
• Forum: 80-Series Tech

Thread 'Third Brake Light troubleshooting/rebuild tips'

May 30, 2021

If your 3rd brake light is not working, working poorly, or half working. Only a few pics and assuming basic familiarity with soldering, soldering irons, and heat. And this is just the tools and methods I used to address the situation on my hands: light was working but it was very dim and half the LED's wouldn't light up.

Shoutout to the MUD member posting this link (can't find it again) DIY Landcruiser Third Brake Light Fix: $0.69 - http://the36thlock.blogspot.com/2010/08/diy-landcruiser-third-brake-light-fix.html. I went with their zener diode voltage - 5.1V They say if the...

• LandLocked93
• 3rd
• Replies: 2
• Forum: 80-Series Tech

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