It has a 4 way flat tow plug. I want to upgrade to 7 way. The rear end is fine, easy plug in harness. The problem is whether or not I need the extra harness with relays that plugs in front behind the passenger kick panel. I don't see an empty 12pin socket there like the installation instructions show. But I also don't see anything that looks like a factory relay for the brakes on the 7 way plug. Anyone know how to figure this out?