Why isnt my tail light working but my brake light is

[zachartley]

Hi I have a 2014 mazda bt50 and I'm having trouble woth my tail lights. On one side the tail light and indicator doesn't work but the brake light does. Brake light is a dual filament globe and both are fine.
And on the other side the indicator and tail light work but the brake light doesn't and all filaments are fine. I switched all the globe to make sure that wasn't the problem but still thr same issue does anyone know what might cause this.
Thanks

 

[DPG]

Welcome to the forum.

There are two different patterns of bayonet studs on the dual filament bulbs. It may be worth checking you have the correct ones.

 

[telectrix]

I'd suspect corrosion of the circuit board that the lights are fitted into.

 

[brianmoooore]

When vehicle rear lights start doing peculiar things, check out the negative connections and wiring to the chassis which are common to more than one light.
Use a flylead with one end connected to chassis or battery negative, and temporarily connect the other end to the earthing connection on the lamp clusters.