03 f-150 xlt ignition power
 

good morning or afternoon I am unable to get power to the sylinoid signal wire from the ignition block tested at wire to negative side of battery( shows 4 v dc). also losing battery power during non-usage. also noted that the truck will start if we arc the sylinoid. we have change the ignition switch assembly and the starter sylinoid (suggested that the ignition switch was worn and creating a bypass of power). also there was some suggestions to remove the replacement ignition assembly and attempt to start it to see if there was an ajustment needed in key switch linkage.so my question is there an overriding safety system, parameter, fuse or relay that prevents this power or is it just a bad wire from ignition block to syliniod?

Thank you.

In order to try to come up with a reasonable answer , is the truck standard shift or automatic trans. Which solenoid are you jumping?

automatic, starter solenoid next to battery on the firewall

Some have had fuses. Good place to start is check all the fuses. Not sure where you are getting the 4 volt reading, but if it is where I think it is you have a poor ground for that solenoid you have to now jump.

checked fuses noticed that the passenger compartment relay #3 is not there but all fuses are ok in the right position. the volt reading is on the starter solenoid signal wire smaller red wire running through fire wall to solenoid post this is a snap fit electrical connector. is was a reading with the ignition switch in the start position with the wire off and a meter to the negative side of battery. we do have normal conditions in electrical system on radio fan and factory key less entry. and starter will engage and truck will run if we turn key to on and arc the starter solenoid.

thank you.

also just verified the under hood fuse panel good.

Last but not least, check the range selector switch (Neutral safety switch).
Have you tried both park and neutral positions? It should be located on the side of the trans. Unplug the plug and look for corrosion.

good afternoon checked the switch assembly for corrosion nothing found. the power module maybe? asked around and they suggested that the engine has gone into theft mode? the theft indicator light turns on when turning the key switch until key is in start position and remains off after. any help greatly appeciated thank you.

Hopefully someone with more knowledge of PATS system will come forth and answer your questions and have a solution to the problem. Does your owner's manual have any info in it to help reset the system?

I have to admit that I have no knowledge about the PATS system (except for what it does and how it works in principle) but if you get 4V between the red wire and the ground (when you should be getting 12) on the starter relay, this means that the remaining 8 volts are being dropped somewhere from the ignition block downstream while the starter solenoid (relay) is energized. This means one of two things:
1 - the starter relay is toasted and takes too much current through its coil, overloading the ignition block contacts and causing the large voltage drop across them, or
2 - your ignition switch starter contacts are toasted (or you have a wiring problem between the ignition block and the starter relay)

For 1: insert a meter (set to measure 10 or 20A DC current) in series with the starter relay, and put the key in start. If the current you see exceeds 1-2 A (for most cars and trucks), your starter relay is gone, replace it.

For 2: Measure the voltage at the starter relay terminal on the ignition block (where the red wire comes from) and put the key in start. If you see 12V, then the 8V are dropped on the wire - wiring problem, If you see 4V, then the 8V are dropped on the ignition switch - replace ignition block.

This should do it ... good luck, and let us know how it goes!