OK here is my story/situation. I have a 2006 F350 6.0 Lariat FX4 LWB. I have been having issues with my truck overheating, I know the issue and how to fix it. It is a bad fan clutch, been through it once before this past May I just have not had the time to change it out. So I got home and did not want to turn it off for a separate issue where if I turn it off once I have ran it the truck will not turn back on without jumping it.

Ok so I got home and for some unknown reason I decided to check the connector for the fan clutch. When I grabbed the connector the wire got eaten up by the fan, it ran for about 30 seconds and then shut off. When I attempted to turn it on the wrench came on the dash and the millage then showed all dashes, when I attempted to start it all went black and nothing happened no crank or even clicking. Not having the time to further mess with the truck I left to work. I got home and was forced to do the fan clutch swap. Once I completed the clutch replacement I attempted to turn it on and it was the same situation as earlier.

So I connected the OBD2 and it would not connect saying connection error. I then searched google and multiple forums for similar issues. I checked everything stated in all the post I found. I checked every single fuse by pulling it out and doing a visual as well as a DVM continuity check, even a voltage check and all where good. I checked all of the relays by pulling them out and connecting 85 to positive 87 to ground, 30 and 86 to the DVM to check ohms and all where good. After hours of searching I found all of the fusible links on both batteries and all checked out with 12 volts after the fusible link there was two on the driver’s side and five on the passenger side. I disconnected the yellow starter wire to the positive of the battery and the engine cranked with the key on the run position and off position. And for good measure I even checked the inertia switch and still no luck. I have run out of ideas and I am not seeing anything else online to check for.

I really would like to figure this out on my own without having to take it to a mechanic. Does anyone have any other ideas or advise?
Thanks in advance.

P.S.
I am going to post this on multiple forums to try and maximize my possibilities for help or a resolution.

 

I will be giving this some thought for you.

 

Well I figured out the issue. I thought I had checked all the fuses but I missed fuse #22. That fixed all my headaches for now.

Thanks.

 

Glad you could figure it out! I was going to scan a couple diagrams I have and post them up for you.

 

I also have a 2006 F-450 6.0. I was pulling a load up hill when everything just shut off but still had lights on the gauges. I could not crank the motor and the OBDII plug cannot read the computer. I tested the FICM and have 48 volts. I discovered that the fan clutch wire had been shredded by the fan, as I just recently had it installed and the mechanic failed to secure it properly. I found a disconnected engine to firewall ground cable, loose starter cable, loose negative battery terminals, as well as the shredded fan clutch cable. I connected and tightened all loose connections, checked all pcm, starter, ignition related fuses and relays throughout the fuse block and could not find a broken fuse. I ordered new fan clutch, new pre-programmed pcm, and new bulletproof 58volt 6 phase FICM which i have yet to install. With my luck I feel like even after new PCM and fan clutch, im still not gonna have a cranking engine but we shall see. My best guess of what happened is that the fan wire was ripped to shreds by the fan blades and somehow shorted out the PCM? sound plausible? no blown fuses to the best of my searches. would a fried PCM prevent starter from engaging? I hope i can swap it with the newly pre-programmed PCM i purchased online. I believe i check fuse 22 but will do a double check. I do have SCT tuner on the truck with an Innovative diesel tow tune. When i attempt to return to stock program, the tuner as well as scan tool cannot connect to computer. Anyone have Ideas! what else I should check? just to give a background of the motor, it has been bulletproofed, just took the truck out of the shop where it got new Kill Devil Diesel heads because i messed up by installing Flex-a-Lite electric fans that could cool the engine down while towing so i went back to stock clutch fans.

 

A shorted fan clutch will prevent the starter from engaging. It can blow fuse F2.22. It can do this without ruining your PCM (which I highly doubt is bad).

 

bismin1, do you think the fan clutch shorting out and possibly blowing the fuse would prevent the OBD2 plug from allowing connectivity to the PCM? I still have to check that fuse, i thought i did but could have overlooked it.

 

Possible. Also, a shorted fan clutch can even prevent it from cranking without blowing fuse F2.22.
Fuse F2.12 is for power to OBDII port (and the cigar lighter).

Does the cigar lighter plug work?
Does the fuel pump come on when the key is turned to on (not cranking)?
Do the injectors buzz w/ key on?

Just an fyi - an electrical short in the fuel heater circuit, the transmission range sensor, or even the shifter handle can cause a no-crank. So can a shorted out v-reference circuit (at any of the sensors that have a v-reference circuit).

Also fyi - The PCM controls the ground for the start relay that is on the fuse panel under the dash. It is a pink wire if you need to locate it. If the OCM doesn't sense neutral or park from the TR (range) sensor, it will not ground the start relay. So, if you have power on two posts at the relay, but no ground ... it is either a PCM issue , the wiring (pink wire circuit), or the range sensor or its circuitry.