RX7 LS1 Swap Wiring Harness | Wiring Specialties Harness kit includes a bypass switch to allow the use of RX7’s High Pressure fuel pump. For proper ECT gauge functionality the RX7 ECT sensor must be installed in the OEM sensor opening on Bank 2 (cylinder 7) location on the LS engine. This is the 1-wire sending unit, NOT the 2-wire and it will require the use of an adapter fitting. Mazda RX7 LS1 Wiring Harness | SIKKY Brand new, plug and play LS1 wiring harness for a Mazda RX7 FD with an LS1 engine swap. No core required. Made in USA. Ready to ship.