My knowledge of Ford electrical systems is limited, and when it comes to late model electronic controls - I know zip.
But I did look at a starting system schematic for a 2001 F-150 and the first thiing that comes to mind is that starting [I]relay[I] as opposed to the solenoid is pulling in. Use this to follow my reasoning - I'll email it to you as well:
You know how GM starting system is; basically ignition switch (through the neutral/park safety switch) energizes the solenoid coil and closes the contacts within the solenoid which provides full battery power to the starter windings.
Ford design incorporates another switch in addition to the solenoid - the starter relay.
It is mounted on the inner fender or firewall and when the ignition switch is closed (and the transmission range sensor senses park/neutral) power is available to the coil and the relay pulls in. When that occurs, the relay closes the main contacts (the relay coil is grounded through the casing/mounting bracket).
Only then (while the starter relay contacts are closed) can the power from the battery reach the solenoid/starter.
To get the truck to crank over by itself the ignition switch must fail closed while the truck is just sitting there. Unlikely anyway, plus I see your friend has already changed the switch.
But the ignition switch does not feed the relay coil directly. It only pulls in another relay (there maybe more than one) within the control system. One of those downsteam relays may be intermittently closing and providing power to the starting relay.
I don't have enough information available to provide a list of the electronic relays involved. I see the GEM (general electric module) mentioned alot but again your friend has changed that.
Here is a good test to determine whether the unwanted starts are coming from the electronic side on the system (PCM/GEM/etc). Or, if it is a simple problem with the normal electric side of the system (by that I mean the starter relay on the firewall/solenoid/starter motor group):
Ironically, the last line of defense to keep power from getting to the starter relay is the DTR (digital transmission range) sensor.
Assuming it is functioning normally, place the transmission selector in anything other than park or neutral. That should prevent any stray/inadvertant signals that are coming from the electronic side from ever reaching the starter relay.
Your friend should try shutting the truck down and then move the gear selector to R or D.
If he does this for a few nights and the self starting goes away - he can assume electronic module issues.
If however, with gear selector in R or D, the truck still wants to start itself up - he can assume that the problem lies in an old-fashioned component. My guess would be the starter relay before I suspected the solenoid.
He can even trouble shoot that side further by pulling the wire that leads from the relay to the solenoid and observing that for a few nights. If it still self starts - its the starter mounted solenoid or the starter itself.
This post has been edited by NorthportTroller: Jan 27 2013, 10:16 AM
Ok, So i did check that wire. The wire on the solenoid (I call this wire the excite wire) ... And it has less than a volt of power at all times. Even in gear.... So its shorted out after the nutreal safty switch.
I keep wanting to just bypass this chit... And find the wire that gets 12v when ignition is activated in start pos... And run a new wire straight to the slenoid