They should be a tact switch, I think. Push on them and they should make a tiny click.
So, I see two switches and an LED.
This
https://www.electro-tech-online.com/attachments/xfspoilerdiaga-jpg.99712/ diagram of yours shows two switches and a resistor.
Something does not add up? Wire colors?
From what I see in the picture, I imagine a 4 pin connector on the other side.
One pin should be common. Call it PIN C
Pushing on switch A should connect/disconnect say PIN U
Pushing on switch B should connect/disconnect PIN D
The leftover pin should connect to say PIN L.
Using, Up, Down, Common and LED.
If you look at this
https://media.digikey.com/PDF/Data Sheets/Everlight PDFs/ds300016.pdf datasheet and look carefully, you will see a flat side on the LED.
That is the negative side of the LED. If you use you meter in continuity, you should have 2.1 when the neg probe is on the flat side and the positive probe is on the other.
When you flip the leads, you should have nothing.
There's always a couple of gotcha's. The LED needs a resistor. That resistor for the most part determines it's operating voltage. It COULD be inside the LED. In a mass produced car, I would suspect not. It could be on the PCB or it could be in the BCM. In reality - no big deal.
The bigger deal is where the flat end goes? Is it common?
If you have the connector, do the wire colors match the schematic?
So, a resistor exists, like in the schematic for the switch or you have the wrong schematic.
another resistor could exist for the LED on the switch.
So, pick a pin and using continuity find an arrangement that you get (push U = beep), (push D = beep ), ~2.1 on pin L with one pin common. Where is the neg probe?
If you don't get two pins with a beep, then one pin may have a resistor to common.