Hello!
I am in a pickle. I have had my third brake light bouncing between working and not working for a few months. I really didn't want to get into the install of the new led strip or pay for the part. So I decided to make my own third brake light strip, similar to what you find on newer cars. I haven't done anything to install it yet. My issue arose when I was testing the harness for the third brake light. I wanted to be sure I was cutting the brake light harness and not the one for the sub. I tried to test the pins in the male side with a multimeter. As you would expect I had to depress the brake pedal as I tested and I used a jack stand leaned on it to simulate my foot. I must have shorted the plug because none of the taillights were on when I poked my head back out (I know they were on beforehand). I wasn't even able to get a reading. I automatically assume its the fuses and check the one in the driver's footwell and the one behind the battery, All are fine. Being my clumsy dumb self I drop both and so on top of being checked, they are replaced and new. I also checked all the surrounding fuses to ENSURE IT WASNT THE FUSES. I then thought it must have been the (BRAKE SWITCH) behind the pedal. 50$ later and no solution. I am quite crossed as it has also triggered my abs, slip and traction lights to turn on (FLUIDS ARE FINE-CHECKED). I am curious if anyone could help, I literally cant afford the diagnositics fee at the dealership until my paycheck comes in but two weeks with no brake lights is not something I wanna do. I checked everything I can think of. I'm going to check the abs fuse as maybe the lights may be on that circuit as well. I am lost so any help would be appreciated. THANKS!

 

Oh and tail lights work so assemblies are fine

 

No mention of the year and model but shouldn't you have checked the schematic wiring diagram in the FSM prior to starting?

https://www.nicoclub.com/FSM/G35/Sedan/2008/EXL.pdf

See page EXL-109,110 in the above link

Since you mentioned intermittent operation prior to your decision to just replace it, shouldn't you have first checked the ground and wiring harness connections first?

Telcoman

 

Is this brake light on the spoiler or on the rear deck?

 

One on the rear deck. Its an 06 MT sedan and I did check the wiring diagram. I wanted to ensure that it was the correct harness before cutting just to be absolutely sure. I didn't check the ground yet but if only one light was intermittent would that be indicative of a bad ground, I assumed since both brakes worked (except third) the ground was fine. Thank you for the prompt response

 

There is one harness connected to the rear deck brake light and it consists of 2 wires. One negative and one positive when u press the brake pedal.

If u have a single LED that is intermittent, then that LED is bad.

 

I am just trying to get my tail lights to work at this point. I am circumnavigating the third brake light regardless

 

Has to be a fuse. Make sure youre checking your brake light fuse and not confusing it with the tail light fuse.