Wiring Issues for 1967 A 100

Ok, I bought all new light sockets and bulbs and replaced old wiring.
I grounded the tail lights.
So, The brake lights work when the head lights are off but when the head lights are on the tail lights are on. The left tail light is super bright while the right one is in good working order.
works like this
Front head lights and turn signals work on (night) or off (daylight)
Tail lights with head lights on: Left is always bright and the right one works as it should
BUT if I put the right turn signal on the left tail light goes out. If I put the left signal on its still off  and when I move the signal to center and turn the heads off and back on the tail lights light up like I said above.
I'm confused
I've checked the fuses
I check the wiring and grounding
I've replaced sockets and bulbs
I'm just wondering where is the break in the circuit
totally frustrating
any help would be great thank you!

2 things,,,,,take the rear lens off,,,,put the tali lights on,,,,see if the lower filament is on,,,,,turn the head lights off,,,,step on the brakes,,,,see if the upper bright filament lights up on both bulbs,,,,make sure you are using 2 terminal bulbs back there,,,,,,(not a single terminal back up light bulb)then you can take a test light and see if the green wire coming out of the turn signal switch is sending a signal to the right rear turn/brake bulb and the yellow to the left rear as you mess with the brake pedal and turn signal lever......

Thanks Don!
Its the high filament (tall one) that stays on the whole time on the left tail light.
I will test it after work tomorrow. Even when the turn signal is on it doesn't blink on the left tail light.
I'll post once I find the solution. Thanks again for your reply!!!

,,,,you can unplug the turn signal switch which cuts off the power to the rear brake/turn signal bulbs and then see if the tail lights work right,,,,,,they are a separate wire and circuit,,,,you either got a bad ground, crossed or shorted wires or the turn signal switch is worn out and sending the wrong signal at the wrong time,,,,,,but check those LR yellow wire and RR green wires coming out of the turn signal switch with a voltmeter or test light,,,,,they both should light when you step on the brakes,,,,,the green one only on right turns,,,yellow on left,,,,,turn signals also stop the brake lights and blink them on turns,,,, 4 way hazard flasher switches also cause problems if you have them......but put a jumper wire or test light to ground and touch all around the sockets when the lights are on,,,,,if the test light glows,,,you got a bad ground