Help! My 2005 Prius which has about 70K miles started having issues 2 nights ago- the dashboard display turns off when I turn the headlights on at night to drive... but I need the headlights on at night and also I need to be able to see how fast I am going/speedometer. Help? Please tell me this is an easy fix. I've googled and even read about turning the Prius into auxiliary mode and going through the computer menu but nothing is working. Help!

  • Welcome to Motor Vehicle Maintenance & Repair! Jul 27, 2018 at 11:10
  • Is the instrument panel dimmer turned all the way down?
    – SteveRacer
    Jul 27, 2018 at 23:01
  • @SteveRacer - That's what I suggested in my answer. Jul 28, 2018 at 13:46
  • Hi there- the the instrument panel dimmer isn't dimmed at all.
    – Mary Carol
    Jul 28, 2018 at 16:30
  • @Pᴀᴜʟsᴛᴇʀ2 sorry, TLDR? Upvote.
    – SteveRacer
    Jul 31, 2018 at 1:08

1 Answer 1


Is there a rheostat adjustment for the brightness of the dash lights? It might be that it got turned down all the way or that it might have gone bad. What you are describing would be normal when the headlights are turned on and this adjustment is focused all the way down, which would basically look like the dash lights were turned off. Try to turn the adjuster up (may have gotten turned down accidentally). If that doesn't work, you'll have to test to see if the adjuster itself has gone bad.

  • Not a 2005 but it seems to have a rheostat: youtube.com/watch?v=bvuGVhmfM9A
    – juhist
    Jul 27, 2018 at 13:24
  • No unfortunately it has nothing to do with the adjuster- but thank you for that suggestion. The speedometer and dash has lights and is just fine but the moment I turn on the headlights, the speedometer and dash goes dark.
    – Mary Carol
    Jul 28, 2018 at 6:26
  • @MaryCarol It still might - often newer cars have a circuit that dims the instrument lights automatically, based on the assumption if you are switching the headlights on, it's dark out.
    – SteveRacer
    Jul 31, 2018 at 1:09

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