Where is the starter solenoid located in the 2004 ford f150?

The starter solenoid on a 2004 Ford F-150 is attached to the starter itself, and considered part of the assembly -- that is, most replacement starters will also include the solenoid. The entire assembly is located on the passenger's side of the engine bay, underneath the exhaust manifold. You'll find that access is better if You have the ability to lift the truck and get in from the bottom. Make sure You use a lift or sturdy jack stands if You go this route. As with any electrical system repair or replacement, it's important to remove the negative terminal cable from the battery before beginning. Failure to do so can result in injury or even death -- and I wouldn't wish death on anyone, not even Ford owners. You can find a replacement starter solenoid alone for between $20 and $60, depending on configuration -- the entire assembly will cost You between $115 and $200, and can often be found remanufactured at the lower end of the price range.