USB C Ports Acting Strange

I am attemting to get a 5 V signal from my 2025 Lucid Air Pure's USB C ports (front or rear). The ports work fine when a phone is plugged in to charge.

BUT, when I plug in a USB C plug there is no voltage on the 5 V lead. I am using the 5.1 k pull down resistors on the CC1 and CC2 leads, but that does nothing.
I have tried adding 1 and 2 ma loads (assuming that the Lucid is load sensing) and that does nothing.

I have tried the my setiup on another USB C supply, including pd, and it works perfectly.

What is the protocol for getting 5v (at very low current) from the cars USB C ports??

@Steve181 watching your thread as I had the same experience. Tried to use the USB-C to power a Vantrue dashcam and could not get power, stuck my iPhone 15 on a USB-C cable and it works.

Duncan C said:

@Steve181 watching your thread as I had the same experience. Tried to use the USB-C to power a Vantrue dashcam and could not get power, stuck my iPhone 15 on a USB-C cable and it works.

Click to expand...

Duncan: It turns out that USB power protocols have become quite robust, but complex, with the user having to request a voltage from the sender supply. There are many USB decoy or trigger boards available to do this.

Unless you are handy with working or soldering to small devices, the method I used was to buy a pre-assembeld cable from adafruit. See https://www.adafruit.com/product/62...7-nAti1NbJdBW1dl6kKqdQ5NxZQFwwat9_kO2HRwCsAY2

Thanks @Steve181.

In Vantrue’s defense, they supplied a charger which works from the 12v port in the trunk, I was hoping I could use generic USB-C to USB-C cable instead.

I will figure something out

Duncan: You have several options:

1 - If you are handy in checking the needed voltage, connector type and polarity, you can use the decoy cable approach that I mentioned.

2- You can buy a 12 V extension cable on Amazon and run it from the trunk to the front via the ski hole in the back seat. That is easy, and can be made to be reasonably unobtrusive. That would fit with your existing charger. I use this method to get high current 12 v (rated for 15A, but I only use about 10A) to the front for my ham radio.

3- Several others have suggested fuse box approahes.

Steve