To find the information you need, you'll have to consult several sources:
* Ford's service manual for a 1990 Ford E250: This is your best bet. A factory service manual will contain detailed wiring diagrams and component information specific to your van's year and model. You might be able to find a digital version online (though often for a fee) or through automotive repair manual providers.
* A wiring diagram specific to your van's VIN: Some online resources might allow you to find a wiring diagram by entering your vehicle identification number (VIN). However, finding one specific to the AC system could be difficult.
* A schematic from an aftermarket repair manual: Chilton's or Haynes repair manuals for the 1990 Ford E250 might include diagrams of the AC system, although they might be less detailed than a factory manual.
* Local auto parts store: Some auto parts stores can access online databases containing wiring diagrams. You might need to provide your VIN for the most accurate results.
Remember to always disconnect the negative battery terminal before working on any electrical system in your vehicle. Working with automotive AC systems also involves handling refrigerant, which requires special tools and training to handle safely. If you're not comfortable working on this yourself, it's best to take your van to a qualified mechanic.
