Rear markers lights come on with brake

[Skytrooper]

I spent the last 2 days screwing around with this. I have the schematics . I just cannot figure what I am missing.

 

[Billccm]

Socket shorted?
Does brake light come on with park lights?

 

[Skytrooper]

When hitting the brake, the lights dim. The right side is dimmer than the left at all times and the back up lights are on too.
I checked the wires and cleaned up some poor quality splices, checked the sockets and cleaned those up too.

 

[oldbee]

Check your grounds first!!!

 

[oldbee]

Broken filament in bulb (1157) touching the tail filament turns everything on. Seen it on semi-trucks; it’ll drive you crazy.

 

[Skytrooper]

All new bulbs. I have been going through the grounds. Does the housing itself need to be grounded ?

 

[PurpleBeeper]

All new bulbs. I have been going through the grounds. Does the housing itself need to be grounded ?

yes.
And if the grounds don't cure it, then you've got wires crossed. Could be the rear tail light/side marker wiring, the plug/wires behind the driver's kick panel, the turn signal switch itself (I think)..."maybe" the headlight switch ??? Check that wiring diagrams + where the actual wires in the car physical run. eg. what wires are close to each other that could get crossed.

I like oldbee's idea about the bulb filaments...never thought of that.

 

[oldbee]

Those big old semi’s show you weird stuff in a hurry, when they put on 100,000 Miles in a year.