car is sunny a12 round headlights

the car have 4 lights (red tailights)

the problem is when you turn the headlights on these 4 lights light up but the inner lights are dimmer than the outside light (all lights should have the same brightness) THEN when you press the brake pedal RHS brake lights go off, LHS works OK.
When the headlights are OFF brake lights work but RHS is dimmer than LHS
Any ideas?

*
RHS = Right Hand Side
LHS = Left Hand Side

Hmm.. i think i get what your saying..

I initially thought bad contact i.e earth points around cluster of light or at contact of the brake pedal switch - causiing a varying/fluctuating amounts of current to go to the bulbs - perhaps?

You could also check that both of the filament wires are intact in the bulbs.

Sounds pretty basic and you may have done all this stuff already - but give it a go if you haven't, might get lucky.

I take it this only happens when you are on high beam and not low beam??

This will sound stupid,
But does the horn work?
My brake lights were doing funky things.
Was the fuse, same fuse for horn and brake lights.

Otherwise, I agree with it being the earth...

Or perhaps a alternator/battery issue?

I've had a similar problem on my wife's old car. When you hit the brakes, some lights get bright, others turn off. After a few weeks, the bulbs would burn out.
I would check and double check to make sure you have the correct bulbs installed. Then check the ground wires to each tail light assembly.
As it turned out, my wifes car had a loose ground wire on one side.

sounds like a loose earth wire somewhere, and as you are having more trouble with one side than the other, I'd look there first.

the problems occurs on low and high beams
and horn is working
checked the bulbs filaments and they are perfect just bought these 3 weeks ago
checked the fuses as well
I'll check the earth.ground wires again...

hello.try to check the wires atach to the headlighs.the problem is the ground wire is not making a good contac or the lamps is not making good ground contac.
(sorry my english ,i am portuguese and not very offen spech or rite in english)

Hey its your 1st post!
Welcome

thanks for the reply will check later

tanks. in fact is the 1