Troubleshooting potential upcoming combination meter failure ('08 Prius)

Hello PriusChat members,

About 2-ish months ago my mom purchased a 2008 blue Prius base w/ package 5 and 99k miles on it (she's up to 102k+ now I think). Upon the car occasionally not starting we identified a dying 12V battery and replaced it with a new one. We also replaced the key fob battery due to beeping when exiting the vehicle after turning it off.

However, right after replacing the 12v battery, the combination meter has not been working consistently. When the engine is cold, the combination meter will not display, however when the engine has been warmed up, the combination meter works fine. We checked all the 12v connections and everything is tight and works well. Everything works well on the car except the combination meter when the engine is cold, and this only started after replacing the 12V.

She's been getting 44-48 MPG on newer winter tires in 0-30 F degree weather, and I usually get 50+ with mild hypermiling in the same conditions, so nothing's off there.

From my research on here I've read that when the combination meter has intermittent failures it's usually due to the unit failing and needing to be replaced, however the failures are not random but consistently only when the engine is cold. With these temperatures the Prius still takes a while to warm up even with a partial grille block, and not being able to verify speed while driving isn't the best.

I have some familiarity working with my 2006 Honda Insight hybrid, but the Prius is quite a different vehicle. Advice and tips appreciated, thanks in advance!