Hi @Kaybee6 (Is it Kay?)

My SNCF 12000 is a 37332 of 2003.
In my case:
- DC motor
- C90 type decoder (simulated adjustable inertia and speed adjustments
- an MM2 decoder

here is what I think:
- I am pretty sure your motor is DC (only 2 wires and in the vast majority of cases, if it runs one direction, it runs in the other
- the decoder MAY need ressting (depending on the type(C90 or later type). This is done writing CV8= 8. This solves many problems but alas probably not with the 37332 with a C90 decoder
- the other possibility is the decoder is fine except for the output stage of power transistors. They are arrange in H form to connect one of the motor wire to + and the other to - and modulating to control the speed. Big speech to say, if one transistor is dead then the motor rotates only in one direction.

What can you do?
- spares are unavailable
here is the exploded view SNCF BB12000
Here is the user's manual User's manual

The best is to replace the decoder by an MLD2 in cable tree form because there is not much space. Make sure that there is a resistor in series when wiring the headlamps (LEDs)
Adding sound to this beautiful loco would be very tricky (so better not)
Cheers
Jean

Either you can control (lights, speed, etc) the loco with your MS2 or not.
- if you can there is an issue with the decoder (not driving the motor in both directions)
- if you can't then need to double check the address set on switches (OFF and ON a few time for each of them, then a real address. Then ask the MS2 to search for a loco while IT IS ALONE on the track

The MS2 can write CV8=8 but I don't think the decoder (M90) will understand it (too old a generation)

If all the above fails, then you may have to replace the decoder (mLD2 wired, I think)

Jean