Hi guys.

On my 1999 TL, when I press the brake, only the 3rd brake light in the rear window comes on. Both on the outside are out (Left and Right). However, when I turn on the lights, both rear lights work fine. I looked at the bulbs and both looked OK, however I had some body work done and I'm thinking that the body shop may have installed the wrong type of bulb? Perhaps? My question is do both bulbs on each side on the bottom get brighter when the brakes are applied? Do both of the lower bulbs on each side also act as brake lights?

The reason I'm stumped and also believe that the brake switch is not at fault is that upon pressing the brake pedal, the 3rd brake light actually works.

 

Furthermore, can it be a fuse since the 3rd one is indeed working?

 

Pull the bulbs and see if they are the correct bulbs (7443). Our bulbs are dual filament bulbs. One for the parking lights one for the brake.

 

its possible the wrong bulbs went in - or didnt get replaced at all

I believe all the bottem are running lights and brake lights
someone with a 99 go out and double ck that please!!

 

I checked. They are correct bulbs and not blown.

 

Which color wire is for the brake lights?

 

There is a brake light failure sensor in the left rear corner of the trunk that the high mount and/or spoiler brake lights don't pass through. Input to this sensor from the brake light switch should be a white wire with a black tracer. Output to the brake lights should be a green wire.

 

Try buying new bulbs from the auto parts store and putting them in before trying anything that costs a lot of money. I had a problem where my parking light wasn't on but when I brake, the brake light worked fine. I changed the bulb and it was good again.