Alternator Booster Harness – RX7 FC3S S5  / RX7 FD Compatible
Give your RX-7 the charging support it needs with this drop-in alternator booster harness, designed for both S5 FC3S RX-7 and FD RX-7 models. This simple mod improves charging performance at idle by adding a diode to the alternator circuit — no splicing, no mess.
Perfect for builds running electric fans, upgraded lights, audio systems, or ECUs that demand steady voltage.