Volvo Repair: 740 wiring, jumper wire, haynes manual

Question
Hi - I recently purchased a 1989 volvo 740 that had the engine switched out with a b23e. After I had it for about a month it would not start, cranked fine but wasn't getting fuel. So I checked the fuses & found that there was a jumper wire between fuse #11(fuel pump) & fuse #12(which had blown). Replaced the fuse & it started fine. Disconnected the jumper & it would not start. My question is why would someone put a jumper wire between these two fuses. My quess is that oviously the fuel pump is not getting power through its normal wiring. Where do I start looking for the fault.


Answer
you would need to remove the 2 fuses and see which one is lacking its power supply.then fault trace the wiring backwards to it source.I really can not say why they did it.you will need a wiring diagram to fault trace the wiring.you can obtain manuals from wwwvolvoinfo.com or try purchasing a haynes manual.