Hello, I drive an 85 mustng SVO and I have noticed that when Im driving during the day, my brake lights work fine, but at night when I have my lights on, you cannot see when my brake lights come on. I have taken the bulbs out of the tail lenses and with the lights off the brake light filiment in the bulb comes on very bright. If I turn my lights on, the other filiment will light up fine. now, when I have my lights on and I push the brake, both filiments light up as they should, but it doesnt change the brightness at all. Whats going on? I need to get this fixed soon because I dont want to be driving with no brake lights at night, any help would be great! Thanks, Ryan

 

I would take a wire to the bulb socket ground and run it directly
to the battery ground.
If the lites get brighter then you will have
to improve the ground circuit.