[GT-ER]

I was installing headers today and I unplugged all 4 sensors and removed them...and forgot to note which goes where.

Am I correct to think that the primaries are the ones with the black plugs on the vehicle harness?

Also, where can I get an O2 harness extension?

[BMWM.D.]

The connector on the pre-cat sensors is black. I thought the post-cat were gray. My headers came with extensions for the driver side only, as they aren’t needed on the passenger side with Kooks. I would have thought that your headers should have come with them if needed.

[GT-ER]

Originally Posted by BMWM.D.

The connector on the pre-cat sensors is black. I thought the post-cat were gray. My headers came with extensions for the driver side only, as they aren’t needed on the passenger side with Kooks. I would have thought that your headers should have come with them if needed.

Right, black primary and gray secondary. Okay good, thanks.

Mine didn't, just need to get one but their are so many connector styles out there that it's hard to choose.

[BMWM.D.]

I believe this is what came with my headers: https://www.kooksheaders.com/2014-20...ion-cable.html

I remember seeing C7 on the package, so I’m pretty sure they’re correct. You could call Kooks to verify.

[GT-ER]

Great, thanks.