ABS pump relay

I have a 92 S-10 Blazer 4x4 with the ABS light on. I did the self diagnostics and it returned a code 65, which is an open pump motor relay. Of course the Chilton manual doesn't mention anything about this relay.

I actually found a new relay at Autozone and purchased it, but cannot figure out where it goes in the Blazer. I looked all over the engine compartment with no luck.

Here is a link to a photo of it:
http://catservices.wrencheadpro.com/SmartPages/partinfo/KEM/ar265.jpg

Anyone have any idea where this thing goes? It is about 1-1/2" square across the opening, so it is much larger than the relays I found on the firewall.

This is driving me crazy. Has anyone run across this thing in their Blazer?

Come on...with all the Blazer owners out there, no one has any ideas? I just know SOMEONE has seen this thing while working under the hood or dash...