I don't think you can do quite what you specified with only one relay. If you are prepared to modify your requirements so that the circuit is reset when the ignition is turned off (rather than off and back on again) then the solution is simple. <!-- Begin schematic: In order to preserve an editable schematic, please don't edit this section directly. Click the "edit" link below the image in the preview instead. --> ![schematic](https://i.sstatic.net/Epd2x.png) <!-- End schematic --> *Figure 1. The modified circuit with all switching in positive lines.* <!-- Begin schematic: In order to preserve an editable schematic, please don't edit this section directly. Click the "edit" link below the image in the preview instead. --> ![schematic](https://i.sstatic.net/H4PT9.png) <!-- End schematic --> *Figure 2. By moving the load positive to bypass the ignition switch the OP's circuit timing and operation will match that of Figure 1.*