In addition to what the two previous posts have said, I am assuming your van was converted to 12 volts. If that is the case, it would appear the PO thought that instead of using a resistor on each accessory circuit, he or she could use one large resistor at the source. I'm not going to comment on the merits of this idea, but you might think about rewiring. Also, there are a lot of discussions in this forum about converting to 12 volts that can guide you in the right direction. There is also a tech tip.
Good-Luck
