Another turn signal problem.

Im still working on that dam 59 GMC pick up.

I got the front signals working by fixing the ground.
Now the problem is iat the rear.

When i press on the brake pedal the flasher stops flashing and all i have is break lights.

Some how the break lights are over riding the turn signals.

The rear lights are 2 wire.
I have a dedicated turn wire to each light that is new.
A wire that is running lights.
And the break light wire.

Some how i need to go 3 into 2 wires but no matter how i wire it i cant have turn signals and brake lights at the same time.

Any ideas would be a huge help.

I realise its not an A boddy but you folks are smartest folks around so i figured id ask here.

Thanks in advance.