On my 1993 RR LWB 4.2l there is a 5-6 inch wire coming from the negative side of the ignition coil that goes to ground and it has a small diode on the wire. I don't see it showing up on any wiring schematics. Is it supposed to be there? Does anyone else have it on theirs? This is not the resistor on the wire back to the ECU. I have a no start problem and am just wondering what this diode is doing here.