Unless GM has changed their basic design, the power for the other doors goes through the driver's master switches. Since you've reported that each door can go up/down using the door switches, it would seem that the driver's switches would also operate them.

Again, unless the basic design has changed, both terminals rest at Ground potential. Then when you select Up, it changes the polarity of one terminal to Positive and the window goes up. When you release the switch, it returns to a Ground potential. When you select Down, the other terminal changes to Positive and the window goes down, then returns to Ground when you release the switch.

Knowing that, you should be able to test the driver's switches as well as the other door switches simply by putting your VOM across both terminals while they are still plugged in. In one direction it should show a positive value and the other direction should show a negative value.

You would really need to test only the driver's switches and one of the doors, at least at first anyhow.

Next to test would be the 2 wires going to the window lift motor. You should get the same results as above, positive and negative values.

 

mm. if the driver side switch is powering the other door switches, it doesn't make sense why 1) the driver door switches won't work for the other windows 2) the window lock button isn't receiving power. there has to be a break in the circuit after the wire splices off to go to the other doors because all of those switches are receiving power.

It's a new switch assembly in there so I don't suspect the switches to not be working correctly and should be reversing polarity when pressed up/down. I bought two new oem switch assemblies and both didn't make a difference.

Do you have a wiring diagram for 2019 malibu? I'd like to trace the power wire back to the culprit, I am pretty sure that there are more than one power wiring going into this assembly and that would explain why only half of the buttons will work on the driver side door.

 

I don't. You can get one from All Data DIY dot com. It's a subscription, but you can do just one month or a whole year.

 

There is a body harness to door harness connector under the accordion rubber boot that goes from the door frame to the door. If you loosen the boot on the door frame side you can check out the connector. You can youtube how to do that as well as disengage the connector to inspect and reconnect it.

It's possible you got water and corrosion in there or that some of the wire pins aren't fully seated.

I did a similar inspection when my driver's front door speaker was sporadically working. Turned out the speaker was blown/failing

 

Thanks MalibuStang! that's a good thought, i'll check it out this week. hopefully it's as easy as that