I even replaced the back battery (with a lawn tractor size (160 cca) -- had a larger one in there that was about 6 months old so - just eliminating that possibility --- have to put power at the front hood fuseblock to get it to start and will stay running but will not boot up from back battery area (aux) only ..-- requires the under hood jump to start ... what could be wrong ?
Maybe go back to square one, install the proper replacement battery? And BTW, my hat's off to you, for the most confusing thread title I've ever seen.
Check the 125A fuse located in the positive 12V battery terminal block (covered by the red plastic piece that you have to remove or pull up when removing the positive battery terminal).
will chekck the fuse .. sorry about title... pulled back muscle and on pain killer - lead acid or sealed doesn't much matter 12-14v source ... will report back on under front fuse 125 AMPERES thx for suggestion !
i unscrewed the 10mm nut holding down the terminal that is under RED post - there is a 100A dc-dc convertor there--- but I don't see a fuse under -- an aluminum plate is there is that the fuse ?
No. Do not look at the relay/fuse box in the hood compartment where the dedicated jumpstart terminal is located. There is nothing wrong with that, since you can successfully jumpstart the car there. The place you need to look is in the rear hatch where the 12V battery is located. Remove the red plastic cover over the + battery terminal and you will see a little fuse block. Find the large 125A fuse and test it for continuity. I think you will find it is open.
The 120A fuse is intact -- no breaks or burns visible through the looking glass of that square fuse on the + terminal for the battery ...
If you have a decent voltmeter, make the Prius READY and measure the voltage at the front dedicated jumpstart terminal. Note that reading. Then go to the 12V battery and measure the voltage there. At both places the reading should be ~13.8V. If you see a lower voltage at the 12V battery, there is a break in a battery cable or a loose connection. Check the negative cable to ensure that it is tightly bolted to the battery negative terminal, and to the body.
Will do Patrick, I noticed that there is significant draw when the front is jumpered -- when the glass pack battery died ( i presume the original) last year .. i didnt want to dump $200 for a new bat so i went for the miata alternative .. of course i didnt have the kit and tried whittling down the terminals to make the origanals fit ) -- this made for intermittents every now and aagain and alot of crystal growth white podwer secretions -- so i took the battery out of the back compartment and into the hatch in a cardboard box so i could make sure the connections are good --- i may have jumped the car wiht inverse polarity from the front .. but if an ecu is fried would it even start at all ?
I get about 12.6 on frt and back before ready .. in READY i get about 14.1 in front and still only 12.6 in hte back battery. I checked the battery cables and the connections seemed to be tight from the terminals to the terminal adapter cables to the battery posts - the NEG. seemed to be tight against the frame and the battery - like I said, it was working with the intermittent connection and now it has better , tighter connections --- but I'm not sure which ecu is susceptable when u have a brief inverted jump in the front .. if that's the aux. computer then ... that could explain it ... but i can still start it by jumping the front and removing the battery and driving and repeating everytime i turn it off ... (not much fun ) ...
This is proof that there is something wrong with the connection from the 12V battery positive terminal to the positive jump start terminal in the main relay/fuse box, OR there is something wrong with the connection from the negative terminal of the 12V battery to the body. You do not have to worry about an ECU or the inverter having failed, if the Prius will become READY after a jumpstart, and can be driven.
I will have to go over the connections in day light as it was getting dark/rainy - will have to go over it very thoroughly and try and restore things as much as possible to original (and reliably working) conditions ... Thx for your expertise Patrick - I do like the gen2 much more than the gen1 -- huge improvements in so many areas -- and a bit of learning curve like that jumping from the front just to be able to open the dang hatch.. but still a great car -- i have been experimenting with some water injection for further gas reduction -- i have seen the gallons per hour go down with some water injection - likely the 500 gph boat bilge pump rig was and variable PWM for control was not helping the 12v system as i didnt have it on a switch to turn off when engine not running....
in my restoration .. when i got to the back battery terminals .. and the jumper from the ground , I had rapped in electric tape, which fealt strong , but upon unraveling saw the intermittent cable shoved into the term. holder with a bolt and that had to be redone /replaced .. so that was the fix .. the NEG. was flaked out - white stuff and not tiight ... -- !
