Car randomly losing 100% electrical power, battery testing good

Maintenance/Repairs
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21

When you say when it fails it has no power at all, I presume you mean no lights at all, even the dome light doesn’t come when you open the door, horn doesn’t work, not dash lights, all gauges don’t work. Brake light doesn’t light when you step on the brake pedal, tail lights won’t come on, headlights either. Right?

If so, when this happens the tech should measure the voltage right at the battery. If that’s ok, then they just have to start from the battery and move forward through the initial circuitry powering the vehicle, find out what’s wrong. Whatever it is, it has to be close to the battery you’d think, for this symptom. No experience w/you make/model, but if this happened in my Corolla I’d suspect in this order

  1. Battery connectors
  2. Battery cables
  3. Master power fuses (sometimes referred to as “fusible links”, located in the engine compartment, usually close to the battery). They can get intermittent cracks in them, work one day, not the next.
  4. An important cable in the engine compartment has got battery acid on it, and the acid has followed the cable down to a wire spice, which is partially eaten away by the acid. I’ve had this happen and it can be very difficult to diagnose. Easy enough to fix though. Check your battery, make sure it isn’t leaking battery acid, even a little bit.
22

On most GM cars, the positive feed into the car the primary connection, comes off the starter. Check the connections at the starter. Also, the grounds are just as important, check for the ground wire between the engine block and the body of the car, usually somewhat hidden back by the firewall…

23

so what was the outcome of this my car is having similar issue

24

I doubt if you will get an answer to this 4 year old thread . Start your own will what vehicle you have and what it is doing. That way the replies will just be for you.

25

Is your car the same make and model as the OP’s vehicle?
If not, you should start your own thread, including the identification of the car that you drive.

26

If you want to know, click on op’s avatar . . . @jimbonator in this case

Then you’ll have an opportunity to send him a private message

Otherwise, it’s very likely he/she won’t know you have a question, because that person hasn’t been active on this website since 2015