Relays under dash question

On the row of relays under the dash, does anyone know what the 3rd relay does and its part number or "control number" .

Also a list of the pinouts would be very helpful. (or a photo of same)

I am talking about the #3 position at the very bottom just above the line of bolt terminals.

In order they are Horn, X-relief relay, ????, fuel pump and then the double size wiper relay.

Thanks everyone for your help.