pcm fuse blows

[Fordified]

01 F350 I had had some earlier problems with this fuse blowing and found some bad grounds and poor connections causing low voltage at the fuse thanks to this forum. I got all that cleaned up and the truck has ran fine for the last few months. Last night I started it up let it warm up and shut it off to load some stuff and no start blown fuse. Removed the fuel heater plug, injector driver relay, and pcm relay, then plugged everything back in until the fuse blew. Seems like it is the pcm, fuse will blow with just ignition on no crank. took pcm out and looks fine no bad pins or corrosion, I do have a dp tuner and have tried with it hooked up and unhooked with same results. Any ideas on how to test pcm or if that is even the problem. Thanks in advance guys.

[NoRalPh]

First, what's the fuse position #?

Second, and here I don't meant to insult you , but, you sure you're unplugging the right plug when you say the Fuel Heater is unplugged?

[Fordified]

No problem, sorry to jump the gun. It is fuse #30 in the cab. I got back to the truck and unhooked the pcm and the fuse still blows. The fuel heater plug that I unplugged is the one right on the fuel filter? I also pulled the relay 30 & 32 in the load center under the hood. Should be for the pcm and injector driver. I am only going off the owners man but fuse 30 powers pcm, injector driver relay, fuel heater, and wastegate solinoid. Unsure where the wastegat sol is. I unplugged the two pin connector on the intake that the air lines for turbo servo go? I deffintily have a direct short somewhere. Anyone got a clue what else that fuse 30 powers up. Thanks

[late_99_PSD]

Your fuel heater is burnt out. Most just unhook it, me included.

#30 should be IDM, fuel heater, and wastegate control (from my owners manual)

[Fordified]

I am unplugging the two pin connector on the filter base right next to the water drain valve on the filter base. Is this the only fuel heater or should I look somewhere else?

[woodnthings8]

You may need to check the wire harness on the engine. Just because the fuel heater is unplugged doesn't mean the wire isn't shorted out else where. Disconnect the engine connector on the drivers side valve cover. See if the fuse blows or not. That will eliminate the engine side. If it blows, ring out the wire and look for a short in it.

[late_99_PSD]

Originally Posted by Fordified

I am unplugging the two pin connector on the filter base right next to the water drain valve on the filter base. Is this the only fuel heater or should I look somewhere else?

You un hooked it and it still blows the fuse.

[Fordified]

If I could I would buy you a beer right now, unplugged driver side main connector and found wires rubbed through on rocker arm cover. Thanks a bunch for the help.

[woodnthings8]

Originally Posted by Fordified

If I could I would buy you a beer right now, unplugged driver side main connector and found wires rubbed through on rocker arm cover. Thanks a bunch for the help.

Not a common problem, but something I have seen before. Seems like the harness on some trucks sits on the valve covers more than the others. I wrapped mine with a teflon tape to protect the wires a few years ago just in case.

[late_99_PSD]

Interesting.... Glad you got 'er fixed