Like to say thanks to Unfazed. Checked the back-up fuse and power to both sides. Checked the connector block under left infil panel and no power there. So rigged up a bridging wire from far side of fuse to connector block and all working. Will leave it like this for a week or so then, if all still OK will cut the original wire to avoid any shorting that may be going on in the loom under the tank. Thanks to Midden also for your input.