1994 F150 clicks one time when trying to start.

The next time the starter just clicks have someone tap on starter with a hammer and try to start at the same time if vehicle starts replace starter. I believe when you checked the starter it tested good because the starter has a intermittent problem. Sometimes working and sometimes not.

did you change your starter solenoid? It is under the hood and when you turn the key it activates the solenoid and lets power go to the starter to crank the engine

What size motor is in your vehicle ?

302 is the engine

I know the earlier fords had the starter solenoid mounted on the fender well but your year vehicle the solenoid is on top of the starter.

There should be a starter solenoid relay on the fender well. There is one on my 96, so I suspect there may be one on your 94. Try jumping it (just for a second) to see if the engine will crank. If it does, change the relay.

Clean the terminals om the battery end and cable end

If stater solinold is on fender well make sure connections are nice and tight and also connection at starter and check starter bolts making sure they are tight.

I have a similar problem. One click is all I get. The starter was under warranty so I replaced that. Replaced solenoid (starter relay some call it) Tried with properly functioning 1000 cold crank amps battery. Wires appear to be good. Engine turnable manually No pulleys were frozen or stuck Full voltage (Above 12.7) getting to starter. And I still get only one click and no starting Any help appreciated....Tks

Turn your headlights on. Try starting the vehicle. If lights dim noticeably, you have a WEAK connection. WEAK does not mean loose connection. Weak means you probably have DIRTY connection(s). A tight connection does not guarantee a good connection. Using emery cloth sandpaper, sand each connection, battery posts, battery cable post terminal, solenoid post, cable ends and connections from solenoid to starter, negative battery cable to frame.