Not sure about vans as we never use them due to harness being too short and the fact that vans are the worst for having a hammered engine...everybody drives PU around empty but most vans typically get driven fully loaded. Serious lack of engine bay cooling also beats the crap out of everything plastic in bay including wire harness and sensors. Also much tougher to work on/tune up so they are least likely to have been well maintained.
Grand Cherokees had reg to 95, Dakotas to mid 90's, I have seen a few Rams that were OBD I but 1 line system and I have seen them duel line...there are Ram trucks that same year has BOTH CCd and PCI Buss, 1500 is CCD and 2500 LD is PCI .if you figure out Chryslers logic behind building cars and trucks, please share :D