Does anyone know where to find the above (asking for a friend)

My guess is a PCB underside of the fuse box, very different to earlier years.

Any help very much appreciated.

 

Service manual says it is in the underhood fuse block but.... it is non-serviceable.

"Important: Relays listed below are non-serviceable Printed Circuit Board (PCB) relays and are internal to the block."
"-- HI BEAM PCB Relay -- HI HEADLAMP - LT Fuse, HI HEADLAMP - RT Fuse"

 

Thanks @MixManSC that's is what I've read too.

The diagram says HI-Beam PCB relay, and as you say it's non-serviceable.

Just watched a YT video on a GMC Silverado, the box layout is slightly different but the format with plastic handles either side looks similar.

The narrator talks about de-soldering the relay mounted underneath, that's my thinking at the moment - some pictures of the underside would be good.

 

Update
Think its P/N GM 20806094 and the underside looks like below, probably take a bit of re-working or just replace (if available)

 

maybe relocate the relay to an empty relay provision on the fuse box. i had to do that for a dodge TIPM fuel pump relay was integrated to the board. benefit was now it had a normal externally serviceable relay.

 

bronxteck indeed that's a good idea.

This 08 has modified headlights, so I'm wonder if they've over-loaded the contacts as some point, who knows.