What is this box for?

[ShawnR]

I'm rewiring everything for the new engine install and I'm trying to figure out what this little box is for. Small kinda silver box behind the AC drier and mounted to the heater box. Mine has a hot wire hooked directly to it from the feed off of the starter. I've completely ditched the original ECU and I'm getting rid of anything that isn't needed. I kind of assume it has something to do with HVAC, but don't know why it would have a hot wire going to it.

 

[Jerryl]

99% Sure it's the blower fan speed relay.

 

[grass doctor]

yes high speed fan relay to be exact ....

GM#10018449 ....discontinued ....​

 

[ShawnR]

Any chance anybody has a wiring diagram for it? Looks to be a basic 5 pin relay. I think it still works, I was just kind of wondering if the constant "hot" wire is normal or something I hacked together 20 years ago and just forgot about.