Need help, reversed polarity installing new aux battery

A different day, different readings. I do not know what is going on, I might be doing something obvious wrong.

I have pulled all the fuses that showed power with the key not even in the ignition slot. The IG1 relay is also pulled. There is still a reading of above 12V at one leg of all those fuses.

 

I have marked the legs where I get a reading of 12.2V below. I put the red probe in the slot and the black one to a metal part behind the fuse box. I will take a photo this afternoon. I think that should be right, because some fuses show power and others don't.





2 M/HTR 15 Outside rear view mirror heater
3 WIP 30 Windshield wiper
4 RR WIP 15 Rear wiper
5 WSH 20 Washer
6 ECU-IG 7.5 Smart key system, power windows, touch screen, electric power steering, theft deterrent system
7 GAUGE 10 Gauge and meter, backup lights, emergency flasher, power windows
8 OBD 7.5 On-board diagnosis system
18 A/C (HTR) 10 Air conditioning system
19 FR DOOR 20 Power windows

I can only imagine how frustrating this must be for you guys. I will take photos and do videos where I can.

 

I completely get where you're coming from, I have on occasion tried to troubleshoot people's computers from afar. Not fun.

 

I love your attitude, ChapmanF

 

OK, for the photos:

IG1 Relay out


Again:



Temporary 100A DC/DC fuse solution:


Fuse box and ground location. X marks the spot I put the black probe at.


And again:


The reading:


I have tried to take a photo of exactly where I have the probes documenting an actual reading, but because of the awkward placement of the fuse box, I was unable to.

 

This what I am looking at. Could it be a blown body ECU?

Edit: I can't seem to upload a full resolution version of this.

 

I suspect I am an idiot. You're always the last one to find out. I will now go and put the fuses in the right order and report back on what happened.

 

Well, today I have learned that I am in fact an idiot and that the Prius, and probably other cars too, work much better when the fuses are in the right places in the fuse box. Who would have thought?

I have OBD, MFD and dashboard lights! On the downside, I do have the red triangle and the MFD saying the transmission lock is on.

I want to thank everybody for their contributions and especially ChapmanF for his patience with me.

I should now be able to use Techstream and figure out why I get the red triangle, right? I feel like I am out of the woods.

 

That was right on the money TMR-JWAP.

 

Sadly, it took me a laptop to figure out that I forgot to connect a wire to the HV ECU. Plugged it in, the engine runs, everything seems to be OK.

In the end, the only thing the reverse polarity caused is a blown DC/DC fuse. Everything else was down to my expert vehicle repair abilities. I did learn a lot in the process and fortunately didn't spend a while lot of money in the process. Incidentally, does anybody in England need a an Engine ECU?

Again, I want to thank everybody, but especially ChapmanF.

 

Yes, @ChapmanF is a star.

It might be useful for others to read the whole story and the aftermath, so here goes:

The ordeal began with it becoming obvious that the aux battery needed changing. There were the usual signs of it going flat in a few days, dim dashboard lights, etc. It lasted 4 years, and my understanding is that that's how long aux batteries last in a Prius.

I proceeded to order a new battery online. Because of the particularities of how and how much, or how little, the Prius used that battery, I figured there was no point in getting an expensive one, so went for the cheapest one I could fine, a Hankook. It was visibly smaller than the Bosch I had in there, but didn't pay much attention to that. Because I am lazy, I started jumping the car from the new battery, every time I wanted to use the car.

One afternoon, I was walking by the car and figured, I might as well change the batteries, it's not a big job. Upon putting the new battery in its place, I failed to notice that the polarities were the wrong way around compared to the original battery. That's when the reverse polarity even happened.

It blew the 100A DC/DC fuse, and a couple of other ones in the engine bay. Those should have been changed, and that would have been the end of the story.

Instead, I wanted to check all the fuses. Not realizing you can actually do it with the fuses in place, I pulled them all first. Then I put them back, one row the right way, the other row the mirror image way. The car wouldn't start. Realizing my mistake, I took out the ones I put in the right way, and changed them to the mirror image way.

I went to the near by Toyota dealership to enquire about the price of a fusible link and ask them what if fixing that doesn't fix the car. The mentioned the ECU. I also asked on a pay site, and the guy said if there is no OBD, it's the ECU. I promptly ordered one. Fortunately it wasn't very expensive.

I took out the old ECU, inspected it, it looked OK. After days on here, I put the ECU back, and put the inside front of the car back together.

Having immersed myself in automotive wiring deeper than I had ever thought I would, on @ChapmanF's suggestion that I take photos of what I am doing, he noticed the fuses were in the wrong way around. Put everything back together, and the car runs.

Now I worked on it today and there is no way I could find to install the new batter. So, I went back to my old ways of jumpstarting the car from the new battery. I figured I'll drive around the neighborhood and I also stood in line at the recycling center for about an hour, never turning the car off.

I drove a but further, once all kinds of warning lights came on, with an annoying beep. I was hoping I could make it home. The red triangle came on. The car started slowing down and would not speed up. I desperately looked for somewhere I could stop. I managed to pull half the car over, the end still on the road. I wanted to turn the emergency blinkers on, they didn't work. I noticed that the clock doesn't work either. I must have put the MFD in wrong.

I was panicking a bit, but figured, I could try hooking up the new battery to the old battery with jumper cables. That got me home. My theory is that the old battery have deteriorated so much now, that it started losing power and the Prius thought that would lead to no good, so just shut down instead.

 

I have borrowed a battery charger for a few days over a week ago, so yes, I do have one.

Yes, after I hooked up the new battery to the car while the old battery is was still installed, it worked as it should.

I will check in the morning. Are you suspecting it might be something else, like the car not charging the battery, as opposed to the old battery just not holding any charge?