No power when off, settings reset, have to use key directly on button to start

I don't know if we've seen this complaint specifically. When I encountered a bizarre deal I could not explain, I replaced the 12v Battery with a new one. In my specific case, the 12v battery did not help. Ended up needing a new charge controller. But anyway, it's not super expensive to replace the 12v battery as something to try.

 

With a good 12V battery and no key fob present, some interior lights and maybe the DRL’s would come on when the door is opened. Press down the brake pedal and push the start button and the dash will display a notice about placing the remote near the start button to start the car. Those would also be the expectations with a dead key fob battery.

No lights, camera, action, would suggest a dead 12V battery. In my experience, applying an outside 12V source to a dead battery in the Clarity will immediately allow the car to power up.

The problem, as described, sounds like a 2-pronged assault of two dead batteries, key fob and 12V. However, the news that a “jump” did nothing, complicates the diagnosis.

 

Was the work performed by a dealer?
Have you picked up the car?
Did they give you a receipt and explain the work that was performed?
If so, was the fuse identified on the receipt?
Additionally, did the receipt have a line item price breakdown: parts, labor, diagnostic fee,etc?
How did they determine that an OBD2 connector caused the fuse to blow?
Do you intend to continue using the OBD2 connector that allegedly caused the failure?

 

Am I the only one who would prefer posters to be upfront about no-standard modifications when asking for help?

If you've connected a third-party electronic device to your car's OBD or other port that interacts in ways not described by the vehicle user manual or you have rooted your head unit, please state that up front.

 

You’re not alone.

Can we put complete, accurate and detailed information on the list, along with answering questions?

There are 21, 10A fuses in the Clarity. The one that failed has been identified as 10(v/a?). The actual help that is needed may be beyond the abilities of the forum members.

 

Just for future reference, the fuse that powers the OBD (also known as DLC) connector is in the under-hood fuse box.
Its designation is B21 (shown on this diagram as "21"): It is indeed a 10A fuse.



I find it interesting that this fuse does power quite a lot of functions (consistent with the OP's symptoms):

 

We can only help you if you help us, by providing complete and accurate information. Read post #3 again. It provides a couple of possibilities based on the incomplete information you had provided up to that point, which was prior to the resolution. We don’t have our hands and eyes on your car, so it is a more difficult process for us to attempt to help you than it is for a trained monkey who has your car and diagnostic tools.

You’ve provided less than complete details on the “Alternative Tires” thread as well. Try putting a little effort into providing more information. And if you want help in the future, you might want to reconsider your decision to accuse those who are trying to help you of not doing “anything to help”.

 

There are so many fuses in this (and most other vehicles) that trying to search them all for a bad one is kind of futile.
Unfortunately the OBD device didn't occur to you (it probably wouldn't have occurred to me either because it was just hanging there unused for a year)
Even if you had randomly stumbled on the blown fuse, you would have replaced it, had it blow again immediately, and still may not have suspected the OBD !

Problems usually seem trivial once you know what the solution is !
A $230 labor fee does not seem unreasonable for the shop to locate the culprit here (especially since it was not original equipment).

It is surprising that the OBD device failed for no apparent reason (and unfortunately it failed with a short-circuit). I only connect mine when I want to use it, but I do have another device that is constantly connected (a blind-spot detection system). I'll remember your experience if something like this happens to me

 

Thank goodness it wasn’t me. And thanks for elaborating on how you feel that I didn’t do anything to help, even though you weren’t referring to me for not helping.

How could anyone have known to whom you were referring, since your post lacked that detail?

 

This could be helpful to me as well. My wife's Volt has an ODB device always connected. It is provided by our electric utility to monitor when/how we charge the car. They pay $10 per month for the information. I'll at last have this to suspect as a start if I have problems with the Volt...