Chillwill - Perhaps you don't need to connect the IG wire. I did and that is why I had to insert a diode. If I remember correctly, and I think I am remembering correctly, that my alternator had to have an excitation voltage on the IG line to get the alternator to charge. Therefore the IG wire had to be installed. However, with it installed, internal feedback through the alternator was getting fed back into the IG line when the IG switch was turned off, supplying voltage to the ECU and keeping the engine running. The diode stopped the feedback and when the switch was turned off the ECU lost power and the engine would turn off.
This is the best of my recollection. I will have to review the schematics and look at the alternator connections again to confirm what I just said. The RV is not at my home at the moment and I cannot get to it for a couple weeks. Also, the schematics are in it so it will be a little while before I can confirm what I did.
'01 Alpine 36 FDDS