Without the manual, finding it will require some detective work:
* Locate the PDB: This is usually a black plastic box under the hood, often near the battery.
* Examine the relays: The relays are usually square or rectangular components that click when activated.
* Use a wiring diagram (found online through forums dedicated to Ford Broncos, or possibly via a subscription to a repair manual service): This is the most reliable method. A wiring diagram will show the correct relay's position within the PDB and its circuit path. Searching for "1996 Ford Bronco wiring diagram" will yield results.
Remember to disconnect the negative battery terminal before working on electrical components. If you're not comfortable working with automotive electrical systems, take your Bronco to a qualified mechanic.