Intermittent problem, 2010 prius not sensing fobs

We have had this problem for a few years now. When the cabin of the car gets hot (ie. parked in the sun for half an hour), generally the car won't unlock (we need metal key) and the car won't power up, giving the usual "key not detected" or "press key to power button, depress brake pedal". If the car is in the garage, or a cloudy day or in the winter, or the AC has just been on, the car will unlock and car powers up (no warnings). We drove all last winter with the car unlocking and powering up every time, perfectly.

As mentioned, this issue only shows up when the cabin/dash is hot, and its been ongoing about two years now. When it occurs, we'd just open the doors and back hatch for five minutes, and then off we'd go. It was getting worse, and our local mechanic won't get into electronic stuff, so we took it into a Toyota dealership. Toyota got back to us (after a one-hour diagnostic saying the problem is occurring is from inside the car, a two-hour dismantling of the dash, and then a one-hour computer test) with their report and quote. The mechanic has stated his computer is telling him that all three main circuit boards located in the instrument cluster assembly are failing and the cost of three components and two ribbon connecting cables ($3800), plus labour and tax will be $4800CAD. That, combined with the previous 4 hours, and 1.5 hours of reassembly, it adds up to $5500CAD.

While our Prius is in great shape otherwise, it is a 2010 with 242,000kms and only worth around $7500. We are having no other issues, or problems, and there are no warnings or readouts that come up. The dash never goes dark, or gives weird glitches. Once the car powers up, we can drive it for hours, park and get back in and drive with no issues whatsoever.

I am not confident that its "failure of the three separate circuit boards" thats the cause, and we're not confident the mechanic has covered all the bases. Further frustration is being only able talk to the three customer service guys behind the counter (Covid protocol). And obviously spending 5500 makes no sense. Our car is still at Toyota, apart. **I'll try and attach a pic of the Dash Cluster Assembly and the highlighted areas that Toyota want to replace.

We are already in this for $700, should we just decide to have them put the dash back together and drive off. Wondering if there is anyone out there that has had this (or similar) problem, and found a resolution. Could it just be the SKS Ecu .. and heat is making it cranky? Faulty SKS Cancel Switch?
{The only other sidebar to all this is ... when the car is not happy, and not powering up, the odd odd time if we really mash that brake pedal down, like hard (with FOB to power button) the car will engage.}

 

Update: The verdict seems to be indeed a problem with the IPC (Instrument Panel Cluster) where the 3 circuit boards reside. The Toyota mechanic is confident he's covered all the bases .. and the code that comes up is U0117. He's checked other components, and gets no other codes, as well as relays behind the junction box, all splice joints up to the IPC, and for any evidence of rodents. He also feels that it's probably just one of the three circuit boards that's giving issue, but Toyota's test only allows for the full IPC, so he can't pinpoint which board.
So it seems we will be looking into a wrecker IPC as opposed to going with new Toyota's parts (that would add up to $3800, plus tax, plus labour.) Toyota did give us a bit of a break on the diagnostic/testing labour charges, which we really appreciated.
Oh well, I'd rather be sippin' an IPA than dealing with an IPC .. but onward and upward. I hope this thread can help anyone else in some way.