During my hookup of the electrical system I managed to supply direct power right into my main ground terminal box for about 10 seconds just enough to completely fry the ground wire of the switch that I was connecting to power.

I checked all the fuses and nothing looked blown (I will check again by pulling each out as I had only done a visual check from the top of each to see if there was a gap in the fuse). So I was able to turn the car over and it ran so I thought I was in the clear without any damage, however, when I tried to turn it over the next day both the emergency brake like and battery light stayed lit once the car was running and a code of P0230 (fuel pump controller) was appearing. As well the dash lights had dimmed once the car had started, which is odd because they were brighter before starting the car.

The P0230 code says that the fuel pump controller experienced a voltage drop or insufficient voltage and I have cleared that code without it returning.

The battery light and emergency brake light google tells me is a result of alternator issues and I may have fried the diodes or voltage regulator in the alternator. To determine if the diodes were fried I used a voltmeter turned to a low AC voltage and I checked the battery while the car while it was off for a baseline and it indicated an AC voltage across the battery of 0.1V and then again with the car running it came back as 0.22V... so I assumed my diodes were shot as I was seeing an AC voltage difference when really there shouldn’t have been any change.

I also noticed that while trialing my car it would randomly stall out and take a while for it to turn back on (cranking pumping the gas etc) I did have some stalling issues before from not having a proper tune yet but the car would fire right up again after it would stall. Now when it stalls I am fighting with the gas pedal and cranking it for a while before it fires. Not sure if this makes a difference but

So now I have replaced my alternator and the good news is the emergency brake light on the dash has now gone out but the battery light is still lit and the dash lights are still dim.

I am wondering if I have somehow fried the voltage regulator within the ECU itself... is there even a voltage regulator in the ecu? Or what else would cause some of these symptoms? I am pretty certain the fuel controller isn’t fried because it still primes the pump and the car does run, that goes for the ecu as well as the car does idle and run but I am not sure if the voltage controller is a separate component within the ECU?

I am at a loss of what the next step would be as I don’t know if I should just be replacing the components that may be fried (ecu or fuel pump controller) without know what the real problem is as it might just fry another ecu or controller.

Any help or suggestions are greatly appreciated as I am not the most electrical savvy person.

Thanks
Ian