Air pump on a 99 Tahoe

[982drhoe]

I have a 1999 K1500 Suburban, and while the inside-engine fuse/relay box has a space for an "A.I.R. Relay (Mark Eng)" relay, indicated by the diagram, but in fact that relay is not used -- if you look at the spot there are no electrical connections for a relay there. So, I'm guessing that the PCM controls the on/off operation of the Secondary Air Injection (eg: smog) pump. View attachment 238198

Mine is also missing ... I have a 2 door Tahoe from California with the secondary A.I.R pump in it... but what explains the empty relay slot?