Why is my USB-C PD not providing power to my MacBook Air?

Thanks for the image.

To be clear, this device does NOT supply power by itself. Right now, as in the image, it is getting power from your Mac's USB-C port and why you can see the device's LED is lit. As connected it cannot charge your Mac.

I don't have it to verify, but I believe you would need to connect your power adapter, via a USB-C charging cable to the USB-C port on this device. It would then pass-thru the power to the cable you currently have connected to the Mac. I do have similar devices like this and that is how they work.

As Tesserax has said, the dock's USB-C port labeled "PD" is ONLY used to accept power from your Mac's power adapter, and pass it through to your Mac via the USB-C cable from the dock to the Mac.

The "PD" port does not pass data, it does not pass power to any device plugged into it. It ONLY accepts power from a charging brick, and passes that power to your Mac.

Charging brick ----> PD port ----> dock ----> Mac

The arrows are pointing 1 way, because that is the only direction the power is going to flow.

No. That USB-C PD port is just a pass-thru port. With the way you have it connected in the photo, if you connect your iPhone to that port, it would receive power from your Mac. Again, there is no battery or power source in this device at all.

I originally responded as your initial post indicated that your Mac was not getting power from this device and I replied with why that is the case.

You need a device that is specified to provide USB-C PD Power Delivery power.

Some display monitors can provide power, some docks that plug into wall power, battery-based power supplies, a Mac or other computer, wall chargers, etc.

With the hardware you're showing, your Mac is providing power into that multi-port adapter device, too.

ugo168 wrote:

I think I understand. So basically I should be able to charge other devices, as long as my adapter is plugged up to my Macbook? And if nothing charges then there is a problem with my adapter?

Your MacBook Air can provide limited USB-C power to connected devices.

That connected device would be the dock.

Whether and how much that dock passes through that power further depends on the dock spec.

Based on its appearance, that dock is a passive adapter for various connectors and removable media.

It isn't intended as a power source itself.

I don't see the specifications for how much power can be provided by the MacBook Air, however.

System Information does have some USB power information available, and there is over-limit protection:

If you see USB Devices Disabled on your Mac - Apple Support

I'm assuming that this is the Satechi Multiport Pro that Apple sells ... correct?

Please upload an image of how you have this connected to your MacBook Air.

It may be possible that this device is defective, and if you got it directly from Apple within the last 14 days, you can return it for either a full refund or a replacement.