Best Path

[pokeyl]

Setting up WB O2 need to get the wiring into the cabin, what is the best path.

Gen3 Thanks.

[Steve M]

I went through the firewall on the right side (when looking toward the rear of the car) of the brake booster.

It is much easier to see if you're willing to remove the driver's side sill...much better view that way, but not required.

[pokeyl]

Did you have to make a new hole?

[Steve M]

This pic shows the wiring from the GMR pickup for my shift light, but you get the idea:

https://i.ibb.co/chGbRXT/3-Firewall-1.png

[Steve M]

I did have to make a small slit in the grommet, but it doesn't take much.