So, I was driving along at probably 45 mph and everything stopped. The engine stopped running, no signals, no flashers, no radio, no gauges, no electrical power of any sort. I coasted/pushed it into the turn lane and got a tow home. It probably sat there for 60 minutes waiting for the truck. I checked for loose cables, popped fuses, but couldn't get any sign of power from it.

So I get it towed home and as it's coming off the wrecker, the interior lights are on. It starts up fine and I back it into the garage. Resting voltage on the battery is 13.3. With it running the battery is at 13.8. I haven't seen a battery fail in a way that would suddenly kill everything, and then recover after time or bouncing around.

I'm not sure where to start. Suggestions welcome.

Just a guess, but there is a main power cable that goes up underneath the fuse box from the battery. I have had that cable get loose inside the fuse box and it caused similar symptoms. It is a PITA to get too, so if you do get that far consider new ends on both sides and new wire in-between, it gets brittle with time.

Thanks OBAK, I will check that this weekend. I may have a short somewhere like this contributing to the issue.

The battery charge dropped within an hour to 12.5v sitting there, so I decided to replace it. With the way it died the battery must have been unable to supply any power (whether due to an internal short, or something shorted in the vehicle is the question). So far it's running well with the new battery. It may have fixed an intermittent knock sensor issue too, but again it will take driving time to really know.

The vehicle has been good so far with the new battery. I replaced the alternator last night because I'm noticing about a .2V drop when the blinker turns on. That gained me better charging voltage (about 1/2v, now charging at 14.2v) but the .2v drop still happens with the flasher. The vehicle has an aftermarket hitch and wiring on it and the wiring didn't work last I checked, so that's my current suspicion.

I checked ground at the alternator, starter, and frame (referenced against the negative terminal) and found 0 ohm resistance and 0v difference. I still need to check OBAK's suggestion, but as he mentioned it's a PITA to get at.

Can anyone comment on the .2v drop with the blinker? It's enough to wiggle the volt meter gauge a little when the blinker is on, so I'm thinking that someone will have seen it if it's typical of this vehicle.

Toyota parts are bullet-proof. Most issues are cause by bad connections, poor assembly or maintenance.

Having said that, 0.2 Volt drop AT battery doesn't seem that bad and should not cause a power failure like you described. However,
please specify where you measured the 0.2V voltage drop:
1) Battery POST itself,
2) or AT terminal?
3) or at fuses?
Yes, those matter. That will identify where bad connection is.

All connections should have bare, shiny metal tightly contacting bare, shiny metal.

Your charging voltage AT ALTERNATOR SCREW TERMINAL should range between 13.5V and 15.1V depending on temperature and state of charge.

Everything in the initial breakdown points to the fusible link. Without it you have nothing. I’ve had the same exact issue due to faulty wiring hack job by the previous owner when I got my truck

I had the exact same issue when my battery neg terminal went loose. It didn't feel loose but the clamp had worn on the bottom--making a VERY poor connection on the top--like a CM of actual connection.

I measured the .2V drop across the battery terminals with the engine running and left signal flashing both before and after swapping both the battery and the alternator. I didn't check the right signal until after the swap, but it's the same at this point.

The electrical connections around the battery have been mucked with. There is a clamp type connection connecting the wires to both terminals and non-fused wiring was run to the back of the vehicle, I suspect for a sound system that used to be installed. They look solid, but also cruddy on the exposed bits. I'll clean this up and see if it affects things.

The neg term is grounded to the body with what appears to be 6 or 8 gauge wire. I'm not sure whether that's a factory connection or something that was added.

85straight, I was ruling out the fusible link because it recovered. I checked the fuses on the side of the road and they appeared to be good.

128keaton, it sounds like you and RAD4Runner are pointing me at those terminal connections. I'll clean them up and see what I get.

Thanks guys!

I had a fusible link get loose and make me get a tow with the '98, just a quick stop to make a call. Once it was re-seated, it worked fine. But with that particular link, I had power to some systems and not others.

I wouldn't worry about the .2v drop either, but you can also test against the headlights or brake lights. Both use a lot of power, and should affect the voltage even more than the blinker...unless there's a short or something on the blinker line, in which case it should seem that right vs left would behave differently.

Like this one? EWWW!


Marine battery terminal like this is better:

Same problem here.

Thanks for all your ideas. I replaced the ends on both terminal cables Christmas Eve. Neither seemed loose or damaged, but the copper was fairly green. I cleaned all that up, but stuck with the same type of connector. The marine connectors would require crimping lugs onto the cables and I don't have lugs for that size. I think the marine variant is designed as it is to allow quick connection and removal of the battery for a trolling motor scenario, rather than an electrical conductivity advantage. That's just just me speculating though...not an expert.

The .2v drop with the signals is still there, but maybe that's just how this setup is. We've driven it around a bit and let it sit for as long as 2 days, without any issues. I think I'll call this one fixed until another symptom emerges.

Have a great New Year!

on my way to work last night, radio, gas gauge, temp gauge, die, truck still running, i get to work shut it off..........nothing, no dash lights, zip
odd thing is, headlights still function
any help appreciated
bill

Did you check things already mentioned above?
What have u done?
Got voltmeter?
How can w help if we do not know what truck we're talking about?

so I have a 94 4runner. the fuel pump stopped, I checked fuses and relays. When I bypassed the fuel pump relay, the pump came on, but didn't start.i replaced the fuel pump relay and same issue.Does anybody have ant ideas?