Won't start! All my fault . . .

I suggest you closely examine the fuses again, keeping in mind that you have three relay/fuse boxes in the engine compartment and one fuse box in the driver's side of the instrument panel, visible when you open the driver's door.

I don't recall whether the relay/fuse box next to the inverter has non-removable fuses built in to the box. If those pop, they probably are not replaceable and the box would then have to be removed and replaced.

If all fuses are good and you still have a problem, my guess is that your inverter is bad and must be replaced, since the DC to DC converter has no protection against a reversed-polarity jumpstart. Unfortunately, the cost of a botched Prius jumpstart can be extremely high, into four digits.

You may be able to purchase a used inverter from a salvage yard, which would reduce the repair cost substantially if you can DIY replacement.

 

If you are referring to the fuse that lives in the positive terminal fuse block on top of the 12V auxiliary battery, then either it is in, or it is not in. If it is not in, then you would have absolutely no power supplied to any circuit.

It is certainly possible that one or more of the many ECUs has also failed; however I think that for the most part they have diode protection against reversed polarity.

It would be best for you to tow your car to a Toyota dealer so that they can provide you with a list of DTCs and their diagnosis. Assuming that the inverter did fail, the eBay part that you listed should be correct.

If you plan to replace the inverter yourself, I strongly suggest that you visit techinfo.toyota.com and download the relevant repair manual pages to improve the likelihood that you can do the job without killing yourself or further damaging the car. There is an element of personal danger involved since you will be contacting the high voltage battery cables.

Good luck...

 

check every fuse. DH would expect to see 4-6 shot. pull em out and look at em. you really don't want an inverter replacement if it was just a fuse.

he's only seen this situation 3 times, and twice required a new inverter. the one with the surviving inverter was jumped off a jump pack.

 

I'm assuming that you replaced the 100A DC/DC fuse. Since you say the MFD does not power up, check the following fuses at minimum:

• 10A ACC
• 15A DOME
• 5A ECU-IG
• 5A AM1

As Galaxee suggested, it would be best to remove and carefully inspect every fuse. If all fuses are good and you have installed a new battery, then the MFD should light up. If the car still doesn't start, then the inverter probably needs to be replaced.

Please note and report the names of any blown fuses that you find.