Extra fuel pump relay?

[M3avionicstech]

Ok so I have a project e30 m3 12/88 and it was gutted and some wire work don't to it supposedly for an s52 at the c101 the engine was removed and it sat for about 15 years until I got it. I was playing around with it the other day and found it has an extra relay installed in line with vi/rd wire that use to go to pin 13 on the c101 now it goes to one side of the switch on this relay the other side of this relay switch goes to the ignition s/w terminal 30 from what I can tell shooting the wires. The trigger side of the relay pos goes to nothing it's a lose wire but I'm assuming it went to an engine harness the negative side of the trigger is from what I can tell shooting wires is going to pin 15 on the ignition switch. I assume if I wire the lose wire from the relay to pin 13 on my s52 harness x20 will work fine, but I was planing on using an adapter harness for x20 to c101 so that wire will have be pulled out an connected to this relay. Any way the big question is why someone would do this because with the s52 harness from what I have read suplies power with pin 13 on x20 Or have I missed something and need to remove this extra relay and re do the c101 wiring also pin 1 from c101 was removed blue wire and pin 18 was removed bk/yl

Anyone have any ideas some different engine installed at some point after looking at the unloader relay circuits I do t think it was done for that.

[M3avionicstech]

Maybe for abs ? Since trigger wire goes to s213?

[M3avionicstech]

Doesn't look like its abs. Maybe just one of those strange things we find when we pick up other people's work. Maybe someone on here will know.