Power at 12v but not at front terminals.

LOL, totally forgot about that post!!

 

Sometimes a picture (wiring diagram) is worth a thousand words.

 

I do have 12v at the connector poking a multimeter through the back crimp so likely thats not . I also tried a second test by inserting a flat piece of copper into the disconencted connector and then a small crocodile jumper from the connector to the + bat terminal and that did nothing ( this test was a little shaky might try it again just to be sure )

 

So if there are no connectors from the jump point to where it says BE1 closest to the battery, in the wiring diagram, and thats just a single wire through to the jump point then likely I have a break in that wire . I shall try bypassing the battery fusible link one more time using a male pin in the car end of the connector and crocodile clip to the +ve bat terminal ( would love nothing better than not having to trace wire to find the break lol )

 

Thanks - I did find it useful.

 

Its definitely a break in BE1 somewhere under the cabin. There was a connector under the rear seat on the left where the battery +ve goes under the cabin it seems to run alongside the fat HV orange wires to go under the cabin and I have continuity upto that connector. So the break is somewhere from rear seat connector to the front jump point .
Any one have any tips on the removal of splash guards etc that protect the HV wires under the car ? Or where does these wires enter the engine compartment ? to much plastic below to get a good view.

 

You just need to pull most of those covers off if I remember correctly. It seems the original Op in this thread had found a place where the cable had a puncture and the wire ended up corroding away. Given you have isolated the open between the connector under the rear seat and the engine fuse box, I would consider going to a salvage yard and getting a replacement. Plus you would then have an idea how it routes.

It could be a job as the harness appears to be built with other circuits. So surgical removal of your desired cable may be necessary.

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BE1 is the name of a connector, not the name of a wire. In fact, it is that connector you found under the rear seat on the left.

The segment from the 12 V battery over to BE1 is part of the wire harness known as Floor Wire #2 (which has a lot of other stuff in it). You seem to have tested out that segment ok.

The segment from BE1 up forward to the fuse box is part of the harness known as Frame Wire. It just has three wires in it: two orange ones from the traction battery, and the black 12 V one from BE1. You seem to have found a discontinuity in that segment.

The Frame Wire is part 82164-47060. It's kind of salty unless you find a salvaged one.

While I would advise anyone against trying to splice or repair the orange HV wires, that might be a reasonable option for the black 12 volt wire, if you manage to locate the fault.

Is it possible the connection at BE1 itself is at fault? Did you check the continuity between the halves of the connector?

 

Thanks for clearing up the names - good to call it correctly.
The continuity between the connectors is good - I guess the easier steps is done, next is the stuff that I find much harder under the car stuff ( or the "surgical" effort .. ugghhh ) and being a Northeast car - the fasteners dont' undo easy .

Thinking next I can try some probing with a sharp needle at the accessible sections somewhere to isolate the break a bit more . Even if the puncture risks later corrosion - I can maybe epoxy the needle puncture somehow. ( I know the orange wires is HV .. will make sure of keeping safe and pull the disconnect too )

Any thoughts on whether that black 12V wire part of frame wire size ? it it 8 awg or 6 awg ? Wondering if I can just run a new one maybe even inside the cabin if I can get it through the firewall rest looks doable even with my limited auto skills . ( I am comfortable with electronics - anything else not so much )

 

Standard #6 or #8 awg electrical cable might be too stiff to easily route and you would still end up splicing the be1 connector from the old cable. I think I would get a junkyard cable and run it in parallel with the old disconnected cable. I would find one of those "bring your own parts" places with a lift and install it standing up.

Before I did any of this I would carefully rig up a test jumper cable from be1 to the fuse box jump point and retest my assumptions.

 

Solved !
The weirdest error... after much frustration and even attempting to use a TDR cable tester (to see if i could detect length of the 12v wire to estimate the break location ), another person helping me by noticing some slight green corrosion near the copper lug on the jump point... so puncturing the insulation like an inch away with a needle showed full continuity - Problem was the crimp between the alu wire and the copper lug .. looked good and solid visually. Removed the lug and re-crimped another lug ( with much cursing and swearing since there is no room and slack in the wire ) and all is good.
The alu wire factory crimp made the wire end bar shaped and the face of the bar that touched the copper lug was somehow magically not passing any current ( that was a Wth moment.. metal to metal crimped where it can;t be pulled off and yet its "open" almost not just high resistance )
Hope this helps someone else - but this doesnt sound like soemthing that anyone else would run into.

Thanks to all that helped and the OP as well - every little bit of info was useful !!

 

Interesting to reread the posts. Of course this thread started in 2019 with another person which can quickly confuse the issue. But PriusCamper was able to foresee the future back in 2019. If he had only warned us about the pending 2020 toilet paper shortages.

Back to the future 2022, Vik Tar had narrowed it down himself.

But was ready to do a deep dive

Finally full circle with green crusties once again accepting the blame. Lesson? Use a good flashlight at connections.

 

LOL - yes all that with green stuff

But a bit more seriously - the green stuff was minimal compared to being a 6awg wire carrying 40A for a few seconds ( I should have got a picture - the outside visible parts were like nothing but a few specs of green ). The main crustiness was in the interface on the copper lug invisible behind the 6awg wire crimp )
I did take a pic of the lug after I yanked it off - its not been cleaned just put away in my museum of fails
See the part visible on top - that was just like that some green just visible from top but rest defintely not looking like it would be a "open"
The crusty part on the flat portion - that was all behind the crimped 6awg wired !

 

Hello all, great diagnosing. I feel like I may have the same problem on my Prius 3 2015. No current is reaching from front to back in my car either. Would anyone be able to pin point exactly where the wires are the go from the front to the back 12v battery so I can check for any breaks in the circuit? Will I have to remove seats? Also what colour are these wires (complete novice here)

 

This thread is for a Gen 2 prius. You are posting in the wrong sub-forum.

 

You can. Start at the battery, follow the wires, test with volt meter or test light, note insulation color, check connectors.

 

is that cable under the aero covers?

 

The information in this thread is for a gen2 2004-2009 Prius. To add gen3 information here confuses things for everyone since the wiring and fusing is different.

Please start a new thread in a gen3 forum and describe what you see, eg what you measure and where along with what still works if anything.

I will say a mistaken reverse polarity jump on a gen3 will cause most things to go dead.