1. Check the vehicle owner's manual. The owner's manual for your El Camino should contain a wiring diagram. If you don't have the owner's manual, you can often find it online or at a library.
2. Look for a wiring diagram in the Chilton or Haynes repair manual. Chilton and Haynes are two popular publishers of automotive repair manuals. Their manuals often include wiring diagrams. You can find these manuals at most auto parts stores or online.
3. Search for a wiring diagram online. There are a number of websites that offer free wiring diagrams for cars and trucks. Some popular sites include:
* [Autozone](https://www.autozone.com/repairguides/Camaro-Firebird-Trans-Am-Monte-Carlo-El-Camino/1987-Chevrolet-El-Camino/info/Wiring-Diagrams)
* [Advance Auto Parts](https://www.advanceautoparts.com/repair-help/wiring-diagrams/wiring-diagram-chevrolet-el-camino-1987)
* [Pep Boys](https://www.pepboys.com/repair/wiring-diagram-chevrolet-el-camino-1987/)
4. Contact a Chevrolet dealership. A Chevrolet dealership may be able to provide you with a wiring diagram for your El Camino.
When using a wiring diagram, be sure to pay attention to the following:
* The diagram is only a guide. It may not be accurate for your specific vehicle.
* The diagram may show only the main electrical components. It may not show all of the wires and connections.
* If you are not sure about how to use a wiring diagram, consult with a qualified automotive technician.
