You don't need the OEM resistor to placed it there,what you got to find out is the resistor's OHM conductivity;With that info you can then choose proper one to add it from any warehouse store such as homedepot.Sorry i can't tell since i never dealt with this issues on the VX,However i can recall running a all brand new wiring to have the radiator's fan working on my old GEO tracker & had to use a toogle switch to turn it on for those hottie summer days.
If you can't figure out the resistor's OMH conductivity call St charles isuzu & ask for merlin,merlin is the man that can save you time,actually you shall give him a call right now (1-636-441-4481) remeber to mention that you're a VX.info member & shipping will be on merlin.