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Discussion Starter · #1 · (Edited)
2003 F350 lariat. Short history:…I just purchased.. supposed to be an alarm issue they took out .. day of I tried to turn truck over (one good battery and one bad battery). I heard injectors buzz, no fuel pump hum.. tried second time no injection buzz but fuel pump continues to run now constantly with key on… went to hook up scanner No obd2 comm.

So as of now truck has 2 new batteries, 2 new fuel filters new 135 amp alternator, new ipr, ipc, ebp, and pig tails , a new remand ficm, new ficm relay and another used pcm… I now have obd2 comm. thx to the used pcm but no ignition power to/from ficm relay/fuse ..main power is there along with ground.. I can jump 12v trigger wires relay and get truck to run but without jumping , the 10a fuse nor trigger/ignition wire of relay have any voltage.. all other fuses and wires good …. I have inspected all pins, connectors, and wires vigorously!!!! So my next step is to replace the under dash fuse box unless others can help ..

My theory: weak batteries shorted pcm, possibly killing fuse box internals.. I have no 12v ignition to ficm relay or fuse under hood, my fuel pump seems to run constant, I know fuse box has a built in fuel pump relay.. would this kill my 12v ficm power (trigger side) and make my fuel pump run constantly? And keep in mind I know my old pcm was blown ..any help or insight is appreciated…. I’ll be running the elm327 with FORScan for Iphone for diagnostic.. as of now no codes are set …
 

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Discussion Starter · #2 ·
If anyone can offer info feel free to respond… and don’t think you need to agree with my theory…

symptoms are: 1) Crank no start- no trigger power to ficm relay or fuse under hood..
2) fuel pump under truck seems to run extremely long or runs constantly
3) radio and entry lamps seem to stay on extremely long
4) when I jump 12v to relay truck fires right up runs but seems to surge
5) only dummy light on is fuel pump related water/fuel lamp..(before I started this project I drained fuel and replaced filters) so in theory water in fuel highly unlikely…
 

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Discussion Starter · #3 ·
I need input on where to go from here… I got the eBay special cjb and installed but noticed right away it not having the same fuse locations as the original…. Anyways I install it and no fuel pump humm period .. Guess it’s wrong one… #%! , *%!, $!*%….
I reinstalled old one checked a few other things still same stuff .. but did notice time delay not shutting down, my power windows are hot constantly until battery saver relay kicks in (30 min)…
So total symptom…..
1)NO FICM POWER TO RELAY / FUSE (under hood)
2) Fuel pump runs constantly key on engine off…
3) Time delay not shutting down till battery saver kicks in (30 min)

I traced the ficm wire tan /yellow from relay (under hood ) to CJB connector and spliced 12v right at connector and got my injection clatter/truck fired right up.. so I know it’s not a short on the trigger wire…. With 12v hooked up key off time delay and fuel pump same symptoms as before..

So if anyone takes the time I need to know where from here??? Another cjb? Another pcm? Or how about a gauge cluster? if you know the pins and procedures to check please lmk …. What volt at what pin to control the tan/yellow wire FOR FICM to CJB from PCM…. What a mouth full ….
Heck all the problems probably comes from the center emblem in grill
 

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A PCM timer is what shuts down the fuel pump relay. If you want to know whether or not the PCM is trying to shut the fuel pump off, it does it by disconnecting the ground to the fuel pump relay (a switch internal to the PCM). You can monitor the ground wire at the CJB connector (for my 2006: pin 10 LB/OG wire on connector C270f) or at the PCM connector (pin 5 LB/OG wire on connector 1381a).

In that fuel pump control (switched ground), you should have continuity to ground with the key on and no continuity a few minutes after the key has been turned to off. If you don't then something is wrong with the PCM. If you do have the ground at the proper times, then your issue is probably that you have a wiring problem - potentially someone re-wired things.

Turning the ignition switch to "ON" should activate the PCM Power Relay. The PCM will get power through fuse 22 in the CJB after the PCM relay has been actuated. This will also turn on the fuel pump (which SHOULD time-out if the PCM does not detect that the engine has started after a certain period of time - say 20 seconds or so).

For my 2006:
Fuses 5 and 18 (hot at all times) feed the FICM Power Relay. Fuse 18 on the low power side of the relay is for relay actuation, and fuse 5 for the power that ultimately provides the FICM its power. First, the FICM itself has to be powered up from the ignition switch. Once it is, it throws the ground that activates the FICM Power Relay that will then provide the "high amp" VPower to the FICM from fuse 5.

You posted:
  • there was an alarm system and it was supposedly removed
  • the PCM was most likely shorted out
  • an Ebay CJB that doesn't match your original CJB was installed

I don't see how anyone on a forum can help you - at least not with any certainty. Too many unknowns, AND I don't see how you can get it resolved with a CJB that apparently wasn't intended for your system.

To be honest, it sounds like a lot of wiring was messed with before you got it.
 

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"resident smarty pants"
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If I were you, I would look at purchasing an Electrical Manual (Wiring Diagrams) for your year model. Mine is for an 06 and may not match yours.


Motorcraft Service sells online access for like $15 for 72 hours(and you can hit print a LOT of times in 72 hours), and AlldataDIY covers one vehicle for a year for something like $30 bucks.
 

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Discussion Starter · #6 ·
A PCM timer is what shuts down the fuel pump relay. If you want to know whether or not the PCM is trying to shut the fuel pump off, it does it by disconnecting the ground to the fuel pump relay (a switch internal to the PCM). You can monitor the ground wire at the CJB connector (pin 10 LB/OG wire on connector C270f) or at the PCM connector (pin 5 LB/OG wire on connector 1381a).

In that fuel pump control (switched ground), you should have continuity to ground with the key on and no continuity a few minutes after the key has been turned to off. If you don't then something is wrong with the PCM. If you do have the ground at the proper times, then your issue is probably that you have a wiring problem - potentially someone re-wired things.

Turning the ignition switch to "ON" should activate the PCM Power Relay. The PCM will get power through fuse 22 in the CJB after the PCM relay has been actuated. This will also turn on the fuel pump (which SHOULD time-out if the PCM does not detect that the engine has started after a certain period of time - say 20 seconds or so).

Fuses 5 and 18 (hot at all times) feed the FICM Power Relay. Fuse 18 on the low power side of the relay is for relay actuation, and fuse 5 for the power that ultimately provides the FICM its power. First, the FICM itself has to be powered up from the ignition switch. Once it is, it throws the ground that activates the FICM Power Relay that will then provide the "high amp" VPower to the FICM from fuse 5.

You posted:
  • there was an alarm system and it was supposedly removed
  • the PCM was most likely shorted out
  • an Ebay CJB that doesn't match your original CJB was installed

I don't see how anyone on a forum can help you - at least not with any certainty. Too many unknowns, AND I don't see how you can get it resolved with a CJB that apparently wasn't intended for your system.

To be honest, it sounds like a lot of wiring was messed with before you got it.
Ok thx for the input , I ran continuity on blue/orange key on - pass at pcm and cjb… Continuity turns off as soon as ignition turns of door open .. so pass as well
Key off set to vm to volts 12.5 from battery + to ground circuit - …..
Fuse 5 and 18 on my 03 is a different setup 5 is not used and 18 is turn lamps/ brake on off switch … but on my setup #20 is ficm relay power it’s hot at fuse in cjb but nothing out of back of cjb at harness tan/yellow wire going to relay / fuse under hood …..

Well anyways I’m going to bite the bullet and order yet another cjb (no more eBay used but working crap)… and when it comes to the alarm splice it all went back wire to wire color to color and truck doesn’t have a factory system from the looks befor I tore into the harnesses it was pretty clean and un touched …
 

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Discussion Starter · #9 ·
CircuitBoardMedics.com repairs central junction boxes.

Assuming that the wire colors were kept the same across model years, the tan with yellow stripe wire should be hot at all times providing power to the low amp (actuating) side of the FICM relay.
Yes circuitboardmedic.com is where I purchased remand. Ficm program/Order to vin #, Fordfusebox.com is where I just ordered remand CJB by vin (no more guessing) 2 day Fedx shipping..
and yes the tan should be hot but isn’t I check wire from ficm relay under hood to cjb .. jumped wire with constant hot and truck starts.. I’m guessing but pretty sure every issue traces back to cjb .. time delay, ficm power, fuel pump issue… I’ll update in a few day’s results of new cjb but keeping fingers crossed..
 

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Discussion Starter · #11 ·
UPDATE: Central Junction Box Arrived quick install fingers crossed… EVERYTHING…. Seems to be WORKING PROPERLY!!!!! I haven’t fired up truck but I now have injector clatter, fuel pump cycles off as should with key on engine off, Time delay and radio go out 20 sec.. as it should….
The bad news is now I got to spent the next few days wrapping-harnesses putting air cleaner box etc… heck of a mess over a damn fuse box.. I’ll touch back in a few days…Thx to Bismic and simple ground test helped narrow the issue
 
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