Diesel Tech wiring Help

03-7.3 F250 4x4

Truck has been running great, drove around Saturday come home cut off.

Go out yesterday and  Nothing in the instruments dash ..gauge's or lights work.
.. radio, lights, door buzzer & all work.

Everything else on truck works just nothing on the dash, will crank fine/ but no start.

Checked all fuses and are good. unplugged all wiring plugs & plugged back in.
Wiggled all wiring.

Checked all ground straps/motor to cab, cab to frame all of them. took them off
and cleaned all & put back on.

Checked all wiring I can see for any broken, can't find any broken.

Plugged a scanner in it and it said can not find the PCM?

So I replaced the pcm relay and that still did nothing.

Any idea's ?????????

Where can I get a wiring Diagram for this truck.

this is for a 99 and up

http://www.thedieselstop.com/forums/f47/7-3l-wiring-schematic-printable-very-handy-257591/

have you checked the reset on the passenger side kick panel?

Larry T wrote:have you checked the reset on the passenger side kick panel?

No.  But doesn't that kill everything.. everything but gauge cluster works & fuel pump works.

Thanks for the link.

PCM / PCM relay & fuses...checked?

GEM module  or ground and or pcm .

FalconEh wrote:PCM / PCM relay & fuses...checked?

All fuses are good and relay but put a new PCM relay in it anyway=no change.

Still checking all wires

You know what is so funny about this hole deal is That I was getting ready to build a stroked BBF like the one Lem
built the torque monster and put it my old junk pickup.

But I had to get the bright  That I could just spend a few k more and get  one of those  
Most RE-(LIE)-ABLE Trucks that every body said was ever made and it would be still running the day I die.

This is the first car/Truck that Ive ever had that I'm sure of one thing.. You better have a new pair of
sneakers on when you leave the yard because there is 75% chance your ass is walking home. At least this time its in the yard.

But I made a fix for it today for when/if I get it running again...

I built a tow bar for the front of my 460 rollback so the next time I leave the yard I'm towing the rollback so I can load
this Super Lemon up and know I'll get back home..

PS:  Did I say I don't like 40miles of wire, sensors, relays, ubr,s,obc's, abc's,nbc, xyz & ma-gee-u-als.

I do like ( KIFS )...Keep it F-king Simple

Have you checked all relays and fuses in the box under the hood? Checked the wire harness on the steering column?

jbozzelle wrote:Have you checked all relays and fuses in the box under the hood?  Checked the wire harness on the steering column?

YEP...and I'm going over everything again today.

Have you checked the wire harness on the PCM where it pokes through the firewall under the master cylinder?

Nothing in the dash lights up? No idiot lights with key on?

jbozzelle wrote:Have you checked the wire harness on the PCM where it pokes through the firewall under the master cylinder?  

Nothing in the dash lights up?  No idiot lights with key on?

Yes this is right...
But everything else on the truck works?  and when I plugged a scanner in it said can't find the PCM... and my Edge tuner says the same thing... putting a new pcm relay in Didn't do anything, still nothing.

I'm like the Ever-Ready Rabit.......... Still looking...

You changed the relay but did you check for power on pin 30 of the relay to see if it has 12V or on pin 85 or 86 for ignition power? Have you checked your fusible links? The IDM, PCM and Fuel pump relays all get power from the same source according to that diagram. One trick I have done in the past is to put 12V to the small power terminal on the GP relay under the hood if it's dead, it will back feed 12V into the PCM and you might be able to scan it then....It sure sounds like a basic battery or key power feed issue though. I'm a diesel tech, when I have time this afternoon I'll look up the diagrams for thw power supplies to see what I can figure out.

BigRigTech wrote:You changed the relay but did you check for power on pin 30 of the relay to see if it has 12V or on pin 85 or 86 for ignition power? Have you checked your fusible links? The IDM, PCM and Fuel pump relays all get power from the same source according to that diagram. One trick I have done in the past is to put 12V to the small power terminal on the GP relay under the hood if it's dead, it will back feed 12V into the PCM and you might be able to scan it then....It sure sounds like a basic battery or key power feed issue though. I'm a diesel tech, when I have time this afternoon I'll look up the diagrams for thw power supplies to see what I can figure out.

No I didn't check those pins for power yet but going to... I took a break from chasing wires and did a draw test Because its also had a slow draw
2-3 days bat. would not go all the way but enough not to crank.. I would just unhook the battery's when done driving.. When I got to the fuses on left side of panel when I pulled # F2:110
the draw went from .39-40 down to .02... that fuse is 50A and goes to ( Ignition switch 11572 Run power circuit )
Do you think that has anything to do with the other problem? should I get a new switch anyway because of the draw.

What I don't have=Nothing in the dash lights up..  No idiot lights with key on.. No start

What I do have=everything= all running lights,dome Lt., radeo LT. and plays. ht&ac fan. elc. seat works, fuel pump works
injectors buzz, LT. for pass air bag comes on for a few sec. and the Door Bell rings. engine cranks

I also pulled back 1/2 of D/S iner finder down so I could look real good at the wires and plugs & unplugged the pcm to get a good look
and its been replaced before and they didn't put the plastic case back on its just sitting on the bracket dose that matter should it have the
case put back on?

Keith Go back to your fuse box I had this happen a few years back it was a fuse didn't show bad ( by looking at it) but I checked it and it was, all my lights were out in the dash....

the Coug wrote:Keith Go back to your fuse box I had this happen a few years back it was a fuse didn't show bad ( by looking at it) but I checked it and it was, all my lights were out in the dash....

Coug did it also not start?

My scanner and tuner are unable to establish Link to PCM

Keith I can't remember if mine started or not I just know the fuse was not blown it was broke, it looked good but conductivity across it showed it was bad. I bought a new light switch and a new turn signal also but I didn't need them so I have extras.  have you searched the net for this problem there are many forums that talk about this kind of deal.... might give you some insight....


http://www.ford-trucks.com/forums/945461-truck-wont-start-weird-electrical-problem.html

http://www.thedieselstop.com/contents/getitems.php3?My%20Power%20Stroke%20Won't%20Start

http://www.thedieselstop.com/forums/f24/2002-f-250-7-3l-wont-start-crank-301711/

http://www.thedieselgarage.com/forums/showthread.php?t=76128

try one of these maybe they will help

Keith have you looked at the ISP on the right front of the intake side of the head? I know mine went to leaking a while back and it affected the engine start I replaced it and everything was fine...but it won't have anything to do with the lights...

Only forums Ive looked at is the one above that the diagram is from Ive joined but cant post a ? don't know why.
Will try again with links you put up.
I'm retesting all fuses tomorrow again and then putting them back in and dropping the fuse box and do a back probe
connector test with a load to see if I have a 12v wire that's not caring the full 12v's under a load.

Keith
in my Book the
#4 fuse is the power point for the instrument panel #20 amp
#22 is engine control #20 amp
#27 is the ignition run feed #15 amp
#35 is the instrument cluster #10 amp
#36 is the PCM keep alive #10 amp
#40 is the fuel pump #20 amp
#41 is also instrument cluster #10 amp
#45 is ignition switch run/start feed #10 amp
#103 is the ignition switch #50 amp  maxi fuse
#105 is the Injector driver module (diesel only)  #30 amp maxi fuse
#110 is an Ignitions switch also #50 amp maxi fuse
#116 is an Ignition switch also #30 amp maxi fuse
#303 Injector module Relay (diesel only)

maybe this will give you a place to check...hope it helps

Thanks Coug but I already went to Ford Monday and had them print me out the whole box diagram.

The only thing that came with my Truck was a big Long Headache.
But it dose run real good when its running. Just never know when its going to decide to run right.

A good rule of thumb that I go by is if you have checked all of the fuses , connections and grounds and your scanner , code reader won't hook up or read , then your pcm is bad. One other thing check the wires and connections coming from ignition switch and fuse links at starter , glow plug , relay /solenoid . also check the fuel bowl heater and make sure it hasn't shorted or broke in side where the filter goes.

If your fuel heater is sorted unplug it down south we really dont need it mine shorted the wire out and melted the pig tail so I had to make a new pig tail that runs the IPR and fuel bowl heater when mine went out it took the pcm out also mine is a 1995. Just something you might want to check also but I did have all my lights in the dash working.

I think I unplugged the f/b heater when I got the truck and changed all the filters but check again to make sure.
Is there anyway a diesel tech at the dealer can check the pcm if take it out take it them???
The dealer down the road from me lets a diesel tech work other people's stuff after hours but he won't come to your house.

I just bought a truck to replace my gas pig 460 to pull my enclosed. I kept it simple and bought a 1995 12v cummins. No pcm, no glow plugs, and gauging from my buddies 94 that has 360k on it no problems.