Has ANYONE figured out how to replace that buried fuse inside the main box? Is there an instruction in the technical manual? (THis is the fuse that blows when reverse polarity is applied during a jump start).
You have to remove the fuse box primarily from the fender. At that point the top and middle sections can be separated.
What a pain in the butt! I think that if I ever had to replace that thing I'd solder on some this wires and mount it elsewhere!
Some have used a bypass but the one I saw had corroded badly and failed again. It has to handle over 100 amps which precludes normal small gauge wire.
Clean up the corrossion, solder 145gauge wire to and external fuse holder. Since it's so rare these blow, like someone hooking a jumper up incorrectly, I'm not going to worry about it. But "if" mine blows, after fixing the problem that caused it to blow, external it is!
As an academic exercise I've put together the way I would bypass a blown 125 amp if were caught on the side of the road in West Texas with only a NAPA store at my disposal. The tricky part would be finding an appropriate fine stranded cable, either a cheap jumper cable or a junk yard piece of the original white fuse box cable.
It’s extraordinarily difficult to separate the center section of the fuse box from the main body to replace the 125 amp fuse. I spent an hour struggling with a junkyard piece and basically had to destroy it to get the fuse out. I am just going to beef up the bypass method on mine and call it a day. as near as u could tell, there are 3 bolts fastening the main body down then a plastic pin that snaps into a hole in the fender. Once the box is free, there are 5 cam/clips that secure the center section to the rest of the box. They have to be simultaneously pressed while you push the center section down. I’m not even sure if you’d have to disconnect ALL the wiring harnesses to gain clearance to separate the box. I cant believe Toyota buried a fuse in an un-accessible location!
In my 2014 pip, the white wire labeled 1e in your diagram is aluminum. The same white wire in a 2010 at the junkyard is copper… Galvanic corrosion here we come!
You can get connectors that work with al and cu. There is also an anticorrosive compound you can use. In any case my scenario would be cu to cu and only temporary. Bottom line - use a lithium jump pack with polarity protection - only!
I don't know if Nyone still needs this, but this is the video I used to replace it. Pulling out the block was much, much harder than in the video, but I managed. Now my car starts, but only for a few seconds before cutting out, also no interior lights etc brand new 12v... so I needed more than this... Best of luck!
The hard to replace125a is in the gen3 cars rather than the gen2 shown in that video, although gen2 is certainly not plug and play. Usually there are more fuses blown.
