You have a 2 terminal "single" ballast system so a 4 pin or a parts house 5 pin ECU (has a dummy 5th pin) will work but an OE 5 pin ECU will not. You (simply & correctly) replaced your melting 4 pinner with a replacement 4 pin & no start & that is what ain't making sense on this cuz the only way it would NOT start is if the new ECU is bad (which is possible) but as you know there is no refund on returned electrical parts that are returned as defective as there is no way of them knowing if it actually is defective or if the underlying real cause of the electrical problem has fried the electrical part that was shotgunned in an attempt to diagnose/resolve it (tho on ECU's I ain't thinking of how another issue could fry one if all connections are closed/not open but it could happen). My suggestion: just get another 4 pin ECU or scrub the Hell out of yours but I must admit that is the worst mess I have ever seen!