Help identifying and repairing chewed wire

To keep rodents out of the interior I would screen all the possible entry points. The main one is cabin air intake, on the passenger side of firewall; you need to remove wipers and metal cowl to access it. See @NutzAboutBolts video on spark plug change for a how-to for that process, video #13 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

there’s a couple more possible entry points at the rear, the cabin air exits, in the corners of the hatch, below floor level. When I screened those recently I opted to remove rear bumper and attached wire mesh cages, secured to the plastic vent frame with screws.

galvanized steel mesh with 1/4” grid is suitable, readily available from hardware stores.

for the already damaged wiring in the engine bay, yeah I’d just clean everything and replace damaged sections with equivalent gauge wires, soldering and using heat-shrink tubing at the splices. Crimped butt-connectors are equally secure, but bulkier.

keeping rodents out of the engine bay is nigh impossible; you’ll need different tactics there, like the one’s you’ve mentioned.

 

Check the operation of both cooling fans.

Offhand, I'd say that looks like the pigtail part of a fan motor assembly. If I'm right, I won't be able to look it up in the wiring diagram—I'd be able to find the connector and wire colors for the car's wire harness where that plugs in, but not for that pigtail itself (it'd just be considered to come with the cooling fan motor, not part of the car's wiring).

Rat got it right close to the connector terminal. Best fix is just buy the repair terminal at the dealer, comes with the right connector terminal already crimped on with its rubber seal and a short length of wire. You pop the old terminal out of the connector housing and pop the new one in. You cut the damaged wire a little farther back, and splice it to the repair wire with a parallel splice and sealant-lined heat shrink.

What complicates that game here is, if I'm right and that's the fan-motor pigtail end, then the part number of the proper repair terminal won't be what you find in the wiring diagram—the part numbers in the diagram are for the connectors and terminals in the car's harness. You'll want the repair terminal of the other gender but same size/style.

I've been able to find those before, with a bit of extra work. If you look through the wiring diagram for the various harness-to-harness connections, sometimes you'll find where one uses the same repair-wire part number you found for the car side of this connection. Then the corresponding pin of the mating harness-to-harness connection will have the repair part number you're looking for. (I hope that made sense.) Of course you want to make sure to find the part number for the rubber-sealed/waterproof version, considering where this connector is. A lot of the wire harness-to-harness junctions are inside the cabin and use the unsealed terminals.

For whatever reason, almost all splice barrels you can buy at regular auto parts stores are butt connectors. Toyota uses parallel splices, which have always seemed more convincing to me anyway. You can find more details through links in this post by Elektroingenieur.

If I'm right and that's a fan motor pigtail, you might just price a replacement fan motor while you're at it. If it's not too pricey, that'd be a plug-and-play solution to the problem, no looking up terminals, no splicing.

 

Unfortunately rodents often chew many wires.

While the rodent chewed the black wire of the radiator fan 1, the black wire is ground.

Top left connector feeds right side fan.


Each fan has a 30a fuse in the engine fuse box. I would just fix the fan ground wire in place.

I doubt it is blowing your tail and marker 10a interior fuse. That circuit goes to all four corners of the car. I would inspect the tail and marker wiring up front.

Then I would disconnect each tail and marker bulb front and back including the license plate bulbs. Remove the individual bulbs where possible and then test with a 10a fuse, a test light or a dedicated current limited device. A bag of fuses might be the easiest

As far as rodent control, you need to be aggressive with the green poison blocks placed around the dumpster and around the car.