2012 Prius v Five... Has anyone tried to fish wire from front door jambs through the rear bulkhead of the front fenders into the engine compartment? A 1/8" (3mm) fish tape can be pushed from the rear of the engine compartment below the hood hinges to the light plastic, flexible fillet at the top/rear of the front fenders. These fillets are not 'seals' or bulkheads or firewalls, they just support the outward profile of the fender at the top-rear. Seems like an easily drilled 1/4" hole and grommet in the fillet would allow access. May go this route instead of back-probing/tapping turn/marker signals in the LS1/LR1 connector blocks.
Hey there, again. It's not difficult to tap into the turn signal wires in those junction blocks. My Scion IQ mirror cover turn signal thread has links to other threads that have diagrams that show/describe exactly which wires/pins are for the turn signals - link is in my signature but here it is: Scion IQ signal mirrors on a Prius v wagon | PriusChat If you prefer running wires into the engine compartment, it's easy to pull wires through the existing grommet above the gas pedal as I did when I installed my rear fog light for which you provided the switch I used. I assume you are thinking about connecting your mirror turn signal wires to the front turn signals. Accessing the front turn signal wires when I installed the DRL kit was difficult. Space is tight and I had to get the front of the car as high in the air as I could on jack stands to do it.
Yes, I used your link (nice write-up!) to identify the junction blocks and wire numbers/colors but am not comfortable back-pinning those nor tapping them in place. The turn/marker lighting circuits are comparatively easy to find, remove and back-pin, at the front of the car. Would prefer not to go in through the fender, likewise not through an existing grommet, unless it is a dummy/unused. Still on the fence as to how to proceed. Thanks.