Digital dashboard display not turning on

It sounds like a bad combo meter. I haven't replaced my 12V battery in a long time. A year ago, my 2005 had the same problem, but disconnecting the 12V battery while the car was running seemed to do the trick (no other way to turn it off). I haven't replaced the combo meter yet. If that doesn't work, I think you'll need a new combo meter which is expensive.

 

The "combo meter" is the same as what you are calling the "digital dash". (Confusing, I know.) Many Gen 2 Prii (Priuses) have had intermittent problems with that piece of electronics, supposedly due to failing solder connections behind the display, a condition that is exacerbated by temperature extremes. An expensive repair is not always necessary. One or more members on this forum have offered to re-solder the connections for a small fee. Details are here: Help! MFD gone BLANK! | PriusChat

Some with this problem have chosen to leave their combo meter in the dash and just continue to drive the car without a display that always works, since the problem is usually intermittent. (Holding the "Power" button down for 3 seconds should always shut down the car, if it is properly parked and will not seem to shut down normally because the combo meter is out.)

As far as disconnecting the battery, I have found it easier to unbolt the negative ground cable from the car than the positive one. Like you, I did not want to risk breaking the plastic tabs on the red cover by prying them, which is the way you would normally loosen the cover.

I hope this helps.

 

my 2008 prius was just changing auxiliary battery over the weekend too, and the digital dashboard keeps not turning on, I found the quick solution is to pull the white color power connector under the big red plastic cover on the battery. However, I am not sure what went wrong, since before I change the battery, the car didn't have this problem.

Thanks if anyone can help.

 

when you unplug the white power connector, the display comes on?

 

Thanks for replying, after unplug for a short period of time and plug back in, everything will work as normal.

and I noticed that this happens when I turn off the car for a short period of time, like went into the store to pick up something. it happens like three times already, for the last two days the car is fine, not sure when it will happen again.

 

it may be a bad combo meter as mentioned in post #2

 

Thanks, bisco. it looks like that is the issue, the new battery has higher voltage make the old capacitor not passing through power.

 

I had this problem to and it was frustrating but i also learned a few things..
The reason these combo meter stop working intermittently is a single capacitor in the unit that goes bad. The capacitor in question is a 100uf 16v unit and this has to low a level of capacitance and therefore goes bad sooner than if it was 200uf 16v. Going bad could mean it is leaking charge ir simply wearing out its capacitance value. The solution is to oversolder another 100uf 16v capacitor or to remove the old one and replace it with a 200uf 16v capacitor. The latter method would seem to be the better option since the old capacitor has lost much of its capacitance holding power. but people seem to have equal success with the oversolder. The old unit may not give the full 100uf capacitance but even if it provides 50uf, the addition of another 100uf capacitor will provide the needed bank of electrons for the unit to function well.

I found that the problem:
1)appeared most often after the car had run for awhile, the was turned off and restarted soon after.
2) occurred more often in warmer weather.
I also found that:
1) if the car is allowed to cool (and the capacitor concurrently empties itself during this cooling and refractory period), then you power on without going to "Ready" for 5 or so minutes before jumping to Ready, the lights return.

Many Prius electrical subsystems are effected by this suboptimal stored charges of this single capacitor. When the combo meter is off, cruise control won't work. Also, you can't electronically unlock the doors and I even noticed power hesitancy and torque decreases when the meter lights were off. I lived with it using the above hacks as well as other listed in responses above before removing the unit and replacing the capacitor. The fix is easy for even mildly competent DIYers, but taking the dash apart is a hassle. One of the main obstacles is cracking the sun/time weakened plastic of the dash air vent housings in cars old enough to have this combo meter issue (my problems started at about 180k miles). I cracked 2 of the 4 vents while being careful. They just kinda disintegrated. The broken off pieces were only cosmetic and didn't cause functional issues, but it don't look good. Good luck with your repairs.

 

2008 Prius with 118k miles. I've been having the dash lights not work intermittently for 6 months. I did the workaround of disconnecting and reconnecting the battery but that got old. I plan to replace the combination meter but dread taking off the dashboard. I'm a procrastinator. It would fail once or twice a week and be hard to predict what made it do it.

I found another workaround a couple months ago that hasn't failed me yet. I figured if the open door icon on the screen was always on the screen would never turn off. So now I leave the hatch open one click all the time. Rain does not get in, though I have not driven fast in hard rain yet. The dash lights have not gone off once. I do have to use the key to lock the car as the fob won't work when a door is cracked. One of these days I'll do the dashboard removal and get a rebuilt meter.