Hello all, I have a question about my step dad's 2005 f150. It's a 4x4 with a 5.4l.

Turning the key to start just does the usual lights going out until the key springs back. Not even a click. It's been months since I bothered lookin at the truck (he says he parked it cause it just randomly started idling BAD, and he's the type to just ignore problems and hope they go away, they didn't, so it sat.)

I'm gettin ready to go mess with it when I have time in the next few days, and if I remember correctly it had power at the small wire on the starter last time I poked it, so I'm assuming the starter is the problem.

However, he swears up and down last time it did this not startin thing "all they had to do was clean some grounds", and is actually gettin mad i wanna replace the starter first to rule it out, cause he's never wrong lol.

So what do you guys think? Should I clean whatever grounds he's talkin about first, and what ones do I clean? Or do I just swap the starter and see how that goes?

Thanks for any input guys, and have a good one

EDIT: Where on earth is the reply button on comments so I can answer people?

 

You should have voltage at the starter relay where the big cable from the battery attaches to the relay.
And when you turn the key to “start” you should have power to the small wire that is attached to the starter relay.
When that small wire has power, it should energize the starter relay.
And, when the small wire is powered and the starter relay is energized, the heavy cable going from the starter relay down to the starter should have power.

If the lights go out when you try to crank the engine, you have a poor connection (or not enough battery).
When you let go of the key and the lights come back on, the poor connection is good enough to pass sufficient voltage to light the lights, but not good enough to pass the high current draw required to crank the engine. More than likely the heavy cable connections between the battery and the starter.

 

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If pats system not happy pcm won't give grd . . The other problem can be the shift linkage underneath ;

 

There are a couple of quick observations you can make to get you pointed in the right direction without crawling under the truck.

1. Observe the THEFT light when the ignition switch is moved from OFF to RUN (not START). If the light fast-flashes, you have a PATS problem and the starter will be disabled.

2. Turn on the headlights and verify they work properly. Turn ignition switch from OFF to START. Do the headlights stay on or go out? If they go out, then there is a problem in the primary battery circuit, either the battery is dead or there is a bad connection or cable. Use voltage drop testing to isolate, if needed.

FWIW, if you're down at the starter already and you measure battery voltage at the small wire with the switch in START, then all of the trigger circuitry is working. Move the meter lead to the heavy starter wire and repeat. If you still have battery power on THAT cable when the key is in START, then the starter is bad. If not, you have a cable/connection problem with that heavy wire.