S80 2001 Trunk Release, Fuel Gauge, Door locks & lights

[dmk614]

All at one time the following components became inoperable:
*fuel gauge
*trunk release from remote key control
*interior lights when turned on inside car
*rear door locks when locked by remote key control
*door lock button on driver & passenger front doors

What could cause all of these things to go on the blink? I've checked some fuses, but all so far are ok.