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I just finished fixing this very problem on our '03 7700. This is the third Ford 5.4 of that erra I have had to fix this exact problem on. Everything works up to an including triggering the starter relay on the firewall. That is what the "click" is you hear in your video when you turn the key. The fix is ........... Replace the starter motor assembly. 65$ off of Amazon for the replacement starter.
The Ford starter motors get finicky with age. Moisture and corrosion builds up inside the high current solenoid that is attached to the starter motor. It hangs up, or burns up, internally and eventually it does not engage. Also, the brushes in the motor as well as the bendix get build up of grit and carbon, causing much higher current draws. The sign of a failing starter is what is described and experienced. -- Intermittent start problems then eventually no start, no crank. --
If the theft light goes out on the dash as it is supposed to when the key is turned and computer systems initialize, and the firewall solenoid engages with a loud audible click when the key is turned CRANK; then the problem is not the PATS or related modules. Once you hear that "click", that proves through the modules. There is nothing between the key and a start at that point except hard wiring.
The problem lies in one of the following:
- internal contacts burnt up and not engaging in the solenoid that is under the hood attached to the firewall, passenger side.
To test the firewall solenoid, take a test light under the hood. Have someone turn key to CRANK. Look for a power signal on the outlet terminal going down to the starter motor.
- there is direct wiring corrosion/connection issue somewhere between the firewall solenoid and the starter solenoid on the starter motor under the truck.
To test the wiring, crawl under the truck with a test light and check for 12V signal at the starter when someone turns the key to the CRANK position.
- internal fault to the starter solenoid/motor itself.
To test the sticking or failed starter, get a wood broom handle. Anything you can stab and tap with will do. Wood preferred. Eyeball the starter motor through the passenger fender well. Locate the solenoid on the starter, the smaller can on the side of the starter motor. Have someone turn and hold the key in CRANK while you tap-tap-tap-tap the end of the broom handle on that solenoid and the motor shells. If the truck fires right up when tapping, .... there you have it.
- One other possibility. Not all trucks have this component. Fuseble link (large fuse) that is along side the battery, is in line with power wire going direct to the starter relay. Link could be burnt, for reasons described above of high current draw of aged components. Check that fuse-link with test light.
In this case, there may have been a problem with old keys or PATS overshadowing the actual starter power circuit issue. I do not believe that PATS or modules is issue at this point. The two videos presented clearly show the systems are working properly up to the firewall solenoid. Do the tests described for the high current power circuit. Am quite confident that ultimately you will be replacing the the starter motor assembly, and/or the firewall solenoid, and/or fusible link; to fix your no crank problem and get your truck back on the road.
Last edited by FaceDeAce; Jan 6, 2020 at 06:57 PM.
Do you have the owners manual? Look in it if you do and see if there is a button to push to deactivate the remote. All I found was, "under the instrument cluster.", and God only knows what that really means. You can also call Ford for a procedure. You might also try putting a new battery in the remote. These are things learned on the web. Apparently remotes for this era could be a real PITA. One guy had a broken door\hood ajar switch which activated the interrupt. I had already heard of early problems with the order of things happening like closing and locking the doors with the remote while the hood was open. This set everything to work out of order which isn't typical. Ford fixed all of this with updates but maybe your truck never got the updates. Granted, unusual possibilities but you never know.
I'm thankful for the consensus this isn't a PATS issue!
Originally Posted by River1
Starter interrupt shuts down the starter. Do you have a red light flashing approx. every 4 seconds that you can see from outside the truck?
Do you have the owners manual? Look in it if you do and see if there is a button to push to deactivate the remote.
@River1 I confirmed: no red light flashing and nothing to that effect in the owner's manual. Given the sheer number of DTC codes, I'll check the GEM after I check the starter... crossing my fingers it's the starter and not the GEM, based on your experience pulling yours!
@FaceDeAce , thank you for the suggestions! I'm new at this, so spent some time googling. I followed the instructions here and tested the starter solenoid electric ground; all good. Will try the broom test you mentioned this afternoon. I also ran out and picked up the Haynes Repair Manual for my truck.
Regarding this:
Originally Posted by FaceDeAce
- there is direct wiring corrosion/connection issue somewhere between the firewall solenoid and the starter solenoid on the starter motor under the truck. To test the wiring, crawl under the truck with a test light and check for 12V signal at the starter when someone turns the key to the CRANK position.
to be specific). Where did you place your leads? Red on the power and black to the metal body of the starter? Or to another piece not directly connected to the starter?
UPDATE: I tapped on the starter with a short wooden handle while my wife turned the key and the truck started up! So, we've confirmed it's a starter issue.
While PATS was a rabbit trail that didn't lead to the cause, it did lead me to pick up the OBD2 cable and use FORScan. After I've replaced the starter, I have a number of other issues to tackle to get my truck back up to speed.
