So i have been having this confusing problem with my toyota. The gauges and LCD on the dash have some sort of brownout going on which causes them to flip on and off during driving.
Additionally, the dash will shut down when trying to do the following:

-Turn signals

-Wipers (front and rear)

-Cabin Fan/AC

-Seatbelt click-in

I have found the dash power terminal and it appears to be getting 8 volts when operational, 6 volts when flickering and 0 volts when non-operational.

How can I fix this? Can I just splice in another 12v ignition activated wire into the power wire I found?

  • There is a problem, and randomly splicing wires won't fix it. You have to find and correct the issue. Sounds like perhaps a loose ground or short somewhere. Check the wiring diagrams for your vehicle to find a common point between the dash lights and the things that you know trigger the problem, that's a good starting point.
    – Jason C
    Aug 7 '16 at 0:28
  • What year is your car?
    – dlu
    Aug 7 '16 at 1:36

You would expect to see about 12 V between the power terminal and ground. Find a place where you can make a clean solid connection to the body of the car, or run temporary wire back to the batter for your ground. Then check the dash power again. If the voltage is low (anything more than maybe a tenth of a volt below what you read at the battery) then you have an issue on the power side. If you are reading close to the battery voltage, then the problem is with the ground side of the circuit. Try this with each of the loads that causes the problem (see if they cause the power supply to drop).

Over time it is common for grounds to degrade and since they are often tied to the body of the car at common points you can see very weird interactions. @JasonC suggestion in the comment is a good one, the most likely place to find the problem will be the common points (which are often grounds).

If the problem is on the supply (+12 V) side, trace the circuit from the battery looking for the point where the voltage drops. Some places to look include:

  • Fuses
  • Any load management relays
  • Connectors, especially those in places that can get wet

Found the problem. Was a blown relay labeled "IG1". Thanks all

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