Fuel Pump Relay Pin (Single Digit) Numbers

[scot850]

This is a good resource for Volvo wiring diagrams. Does not cover P80 or older:

https://volvodiag.com/ewd-online-eng/

Neil.

[JDS60R]

If its a micro relay ,The two larger blades 3 and 5 carry the current to the pump when closed by the coil.. When pulled from the fuse box one of slots should have power. The other is the wire to the pump. Jumping those 2 slots will make it run constant Diagram added
Terminal/Pin number and size

Connection
1 (86) - 4.8mm Coil
2 (85) - 4.8mm Coil
3 (30) - 6.3mm Common connection to NO & NC terminals
4 (87a) - 4.8mm Normally Closed (NC) - not present on 4 pin relays
5 (87) - 6.3mm Normally Open (NO)