I have a 93 940 Turbo Wagon
Working components: Left Right Signal Lights, Reverse, and Tail Lights,

Malfunctioning: No Brake Lights (including Back Window).

I have already replaced the Pedal Switch. Did not resolve.

Fuses are good, Bulbs are good.

Is the double decker the last resort?
I will attempt to isolate the issue to the Big Red Double Decker one.
Where is that located?

 

Red double decker relay, behind ashtray cubby is your best bet in this case... First thing I'd have addressed.

 

I also had the same problem not too long ago and it ended up being the red bulb failure sensor/relay part # KAE 1362370.