Intermittent Electrical Issue

[m85476585]

A friend has a 2012-ish SR5, and it's started having intermittent electrical issues. Basically, the electrical system completely stops working sometimes, but then resolves itself later. When it's not working, it won't start, no lights come on, and it won't unlock with the remote. It's basically completely dead. It usually resolves itself, and after that the clock says 1:00 and everything else works normally. It's done this about twice now. So far it only happens when the vehicle is off, not while it's running. Any ideas what could be causing this? Since it's an intermittent issue, it would be hard for the dealer to diagnose.

She says the battery cables are not loose, but I'll double check. And I'll measure the battery voltage when I have a chance, but when it works it starts normally, so I don't think it's a low battery. There are no mods or aftermarket electrical changes that I know of.

 

[DannyLlama]

Any after market installs? Stereo, lights, communications equipment?

 

[m85476585]

Any after market installs? Stereo, lights, communications equipment?

No, it's all stock.

 

[007Tacoma]

That's no good...

Sorry, but something that major should be looked at by a mechanic. Electrical issues are like gremlins with ADD in a vehicle. Especially if the vehicle has been abused or bought used (and likely abused).

If your friend can't afford a mechanic, here are things to check out:

• main ground
• starter positive
• main harness
• interior harness to control unit under dash
• engine harness

It could be that an animal of some kind has gotten to the harnesses, or it could be a loose connection, or it could be a corroded connection, or it could be an unknown aftermarket part or "fix" that someone did that the owner is unaware of.

In any case, best of luck to your friend. :behindsofa:

 

[1engineer]

My money's on a corroded positive terminal.

 

[MeefZah]

Almost certainly a battery or battery cable issue. The info you presented points to it:

Only happens when the engine is not running
Everything electrical is dead

My best guess if the cables and connections look okay is there is something internal to the battery that is damaged. The problem with that is, when you check the battery, it may check out okay. Personally, I'd check the battery, check as much obviously exposed wiring and connectors as you can, and if you find nothing, I'd replace the battery and continue to monitor the situation.

 

[SATSTRAIL]

If it's not the battery itself (likely not since its intermittent) then it's usually a connection issue, ground, possibly positive. Corroded terminals should be very visibly obvious. Some not so obvious issues could be internal corrosion built up in the negative cable or other ground points. Those items need to be tested by means of a voltage drop test. Simply testing for continuity will not cut it...

 

[m85476585]

It turns out it was just a loose battery terminal. It was just slightly loose, so not readily apparent. Luckily it wasn't anything more complicated than that.

 

[007Tacoma]

It turns out it was just a loose battery terminal. It was just slightly loose, so not readily apparent. Luckily it wasn't anything more complicated than that.

Glad to hear you got it resolved!

 

[DannyLlama]

It turns out it was just a loose battery terminal. It was just slightly loose, so not readily apparent. Luckily it wasn't anything more complicated than that.

I have been on this forum for 4 years and never seen a complicated electrical issue complaint, unless it involves after market installs