Mil-spec Tucked 13B Harness (FD3S/Rx7) This wire harness is made specific for a RX7 FD3 Chassis, not intended to be used for a 13b standalone engine harness. For "Right hand drive" customers, the ECU type will be for the earlier model (Our harness does not support the Austrailian 16-bit ECU's from 96-98) rx7 fd harness | eBay Find great deals on eBay for rx7 fd harness. Shop with confidence. Skip to main content. eBay Logo: JDM FD3S Mazda RX7 Series 7 Fuel Tank Cover and Pump Wiring Harness FD 1996 RX-7. Pre-Owned. $75. From Canada. Buy It Now +$17 shipping. Haltech Elite 2500 EMS ECU with PNP Adaptor Harness Kit for RX7 FD3S-S7 8 96-02. Brand New.