I have a sort of off question. I am trying to build up a very one-off kit car, and I happen to have the original wiring harness and ecu to my rx-7 in a box. The engine side has some bad wires. If I cut out the engine wiring harness pieces and leave everything to run the chassis, i.e. the lights, suspension, and interior; will it work ok if I install it with a stock ecu like this? Just to run a chassis with all mazda oem parts plugged in.

 

The ECU (engine computer) has nothing to do with the Lights, suspension, interior. It only controls the engine.

The CPU (body computer) controls the turn signals and warnings.

So a spare engine compartment harness that had all engine functions (such as sensors, etc) removed would have no effect on operation of the car as long as the interior and dash harnesses were intact.

 

Oh, okay! I didn't realize there were two different units. I haven't gotten too far into mazda wiring harness territory yet. Wish I'd been then one working on this car from the start!