Brake lights - tail lights

Good evening everyone

Here is something that i cant understand....
During daytime, when the lights on the 62 arent on, everything works fine.
Brake lights, turn signals, etc.....

But when i need to turn on the lights at night, the tail lights are on, but nothing else happens when i press the brake pedal....and same thing with the turn signals !!!

But as i said, during the day, if i dont put on lights, everything works nice.... turn signals and brake lights....
Any input would be really appreciated.

Thank you

Hi

Look the négativ and electrique connection.

Test with a cable + and -

Yep - ground is my guess as well.

Thanks for the replies
Do you think a faulty ground would affect the brake lights and turn signals only at night when lights are on, and be correct when lights are off during daytime ????
I really hate working with car electricity....real pita for me. How do i look for a bad ground ?? Thanks

If you haven’t found your problem here’s another idea. Guessing here but some lighting functions are routed through the turn signal switch. Problem may be there since it seems to somehow involve that function whether it’s a ground or something else.

Sounds like you are grounding your signal circuit through your headlights. Look at the grounds first. Battery to block, block to chassis. If those check as low impedance then pull the headlight switch. I did not realize this until I looked, but the headlight switch actually provides the +12 for the whole lighting system.
Main wiring

Keith