Hi guys

I have a 2002 Volvo S60 which has developed an annoying problem with the boot not being able to be opened with the handle switch, only the key fob or the key.
At the moment when the engine is turned off the only way I can open the boot is either mechanically with the key or using the boot opening function of the key fob. The handle switch does absolutely nothing. When I turn the ignition on or off this triggers the boot to open and if I try and use the handle switch with the engine running it blows the fuse to the rear light clusters and the numberplate lights but does open the boot most times.

Today I had a probe with a multimeter on the resistance setting testing it on the wires that lead from the handle, from the lock mechanism itself, and up from the wirejoint that runs behind the left light clusters out of the bodywork into the boot lid, to see if any of the wires were broken.

All of the wires and connections showed resistance on the meter in the same way as a piece of new speaker wire does (so I assume are patent), except for a small brown and blue wire which runs from inside the boot of the car up to the first joint in the boot lid where the wire splits to the lock and the handle, which showed no resistance.

Because of this I am assuming that maybe this wire has a break? However I bridged it with a piece of new speaker wire which then showed a resistance on the meter but did not solve the problem.

I have changed the latch mechanism giving the same problem as before, and tested the switch in the handle using the meter which shows resistance when it is depressed and held.

I don't know enough about car wiring to go any further and am at my wits end now so would greatly appreciate any help!

Thanks very much!