Rick's Free Auto Repair Advice

Flashing dash lights

Diagnose and fix flashing dash lights

If you turn the key to RUN or START and you see flashing dash lights chances are very high that you have a severely discharged battery or corroded battery terminals. Here’s why that’s the most likely scenario.

Computers go bonkers at low voltage

Automotive computers need at least 10-volts to operate properly. When voltage drops to 10-volts or less, all bets are off on proper operation. The computers can shut down completely or cause erractic behavior. In the case of instrument cluster or dash lights, you may see the dash lights flashing or they may light and then go out immediately.

Diagnose flashing dash lights

The first thing to check is battery voltage and condition using a battery tester or voltmeter. Set a voltmeter to DC volts and touch the black lead to the negative battery terminal and red lead to positive battery terminal. Anything less than 12.2 volts is considered a discharged battery. That doesn’t mean it’s toast, but it does mean you’ve got some issues.

Next, do a battery load test. See this post on how to test a battery.

If the battery shows high voltage….
Clean the battery terminals. See this post

©, 2019 Rick Muscoplat

Posted on by Rick Muscoplat

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