2003 F350 7.3 4 x 4

So I came across this thread from 4 years ago:

https://www.ford-trucks.com/forums/1311541-engine-control-fuse-blowing.html

I have the same problem, I've just blown two fuses, in fact one blew as I was replacing it, I think it's either fuse 22 or 23, but it is the engine control fuse. It's actually on the side of the road right now I went to the auto parts store with a friend to get a replacement fuse..

On my way back to the truck here momentarily, the above thread mentions disconnecting the fuel bowl heater, and he stated that he did not have the problem again.

Does anybody have any new recent information on this one? On my way back to the truck right now to disconnect the fuel bowl and replace this fuse..

The last time it blew, which was about a week ago, the truck had the opportunity to not run for about two and a half hours, before I was able to figure out what the problem was. This time I immediately knew what the problem was, because I heard the click in my truck died.
This was literally about 20 minutes ago. So I think because the truck was still hot this time is why the fuse blew again. But I'm not sure.. (the temperature hypothesis, could that validate the fuel bowl issue?)


Thanks again guys and gals..

Jeff

 

Jeff, sorry to hear about your troubles.

Yes, that is a known issue if the fuel bowl heater becomes corroded and shorts out.

Disconnect the fuel bowl heater on the backside of the fuel bowl and replace the 30A fuse. If it continues to blow, you need to start looking for a short of some sort. We can help you track it down, but before going into great detail, let's hope the problem is just the fuel bowl heater and an easy day!

Keep us updated.

 

Hey Sous, thanks for the response.

I did exactly that, disconnect the fuel bowl heater. Replace the fuse, which is a 20 amp fuse. Turn the ignition and it immediately blew again. Then thought that maybe the short was somewhere not necessarily in the harness but maybe in the wiring, so I actually found the 30A fuel bowl heater fuse space 105.. replaced the 20 amp fuse again for the engine controls, and it blew again....

I saw some talks that it could be the harness on the driver side. I fiddled with that a little bit, couldn't really look at it as I'm on the side of the road. Another fuse, blew..

Waiting on a tow truck to have it towed to my house, reluctant to have it towed to the shop as I feel confident that I can find the problem. And I don't want it sitting at the shop for the next week and a half two weeks when I will probably be able to track down this short..

Yes please, what are your thoughts and ideas? How can I troubleshoot where the short is coming from.. that I can find the wire...

Thanks again.

 

This work sheet will tell you a little about the fuel bowl heating element and how to get to it and take it out. I unplugged my 'Fuel Bowl heating element' over ten years ago. You do not need it. If you 'do' 'need it'.... you have bigger issues than the heating element.
https://www.dieselorings.com/docs/FuelBowlRebuild.pdf

https://www.dieselorings.com/instruc...formation.html

https://www.dieselorings.com/

 

Hey Sous,

I just remembered, I did some steering tube bushing work to the truck in the last 3 weeks to a month, where I dropped the 13 mm nuts to drop the steering column.. good possibility I may have crossed some wires or did something down there, I'll take a look at that..

 

Get to a safe location and then start looking for the issue.

Your thought of a starting point is a good idea.

The last thing changed or installed is the first suspect when a problem arises. Are you referring to the "PCM" fuse as the "engine control fuse"? If so, you should not be getting a wait to start light .

Your 2003 should have a fuse panel that looks like the one below, is that right?



I also see where fuse position 22 is Engine Control with a 20A fuse in it, like you stated and I misstated. The 2000 - 2001 trucks are different than the 2002 - 2003 trucks, my apologies.



Without putting yourself in danger, look at the battery terminals, the harness ground in the corner on the driver side near the firewall, etc... Just look around for anything obvious while you wait for the tow truck to get you home safely.

EDIT: If you don't have a copy of the owners manual with the fuse diagram in it, the link below is to the owners manual.

https://www.ford.com/support/vehicle...owner-manuals/

 

Thanks sous. It's raining in Central Florida today oh, I actually just had the truck towed to my house a couple of hours ago. What do you think about this?:

Well first off, do you agree that this is not the common problem with the fuel bowl? As I removed the fuse from the fuel heater and in addition to unplugging it, inserted a new fuse and it blew.

It's on my driveway, and it has had time to cool down, I want to insert a new fuse tomorrow and see if the problem continues. My hope is that it will. My anticipation is that it will as well. However, what if I put a new fuse in and the problem goes away for a little bit. I wonder what that would indicate?

I basically just want to duplicate the way that I rectified it last week, which was inadvertent, but it cool down, then located the problem fuse, inserted a new one and then it was fixed for about a week..

Well try not to think about that too much, I'm going to do that tomorrow. I hope that fuse blows. Then I'll start searching for wires that are shorting.

I don't want to search around, find a wire that I think is grounded out, fix it replace the fuse, truck will work, but then the problem made manifest next week when I'm driving to Jacksonville. I want to rule out any temperature related issues..

 

I agree with that, it still blows when unplugged and additionally I remember reading that the 2002-2003 trucks came with an updated fuel bowl heater that doesn't short out like the earlier ones.

 

Thanks BigB, I figured not. I'm not the best of DIYers, but even on the earlier models that it applied to, I wonder why Just pulling the Fuse wasn't a better corrective action.. No issue with possible grounding from Plug as a result of shifting/insecure Plug. Fuel Bowl Heater has it's own Fuse.

Well, hope I have some good info tomorrow.. I.e. Found a grounding wire..

 

Does anyone have, a wiring diagram or electrical distribution diagram for the engine control? I'm pretty sure fuse 22 the spice to multiple components. I'd like to have that handy tomorrow so that it can help me diagnose this short.
Or if anybody knows what is on that fuse that would be great. I guess it would be I DM, PCM (relays), fuel heater, possible glow plug relay, and maybe a couple of other things .


Thank you much.

 

I found this wire diagram, I believe it has the info you're after.

 

In addition to what our friend has posted above, below are some tips from Mark K. on testing for shorts to power and ground.

Quote source: https://www.ford-trucks.com/forums/1...l#post19916903

Quote source: ​​​​​​​https://www.ford-trucks.com/forums/1...l#post19918627


Good luck to you and keep us posted! ​​​​​​​

 

Thanks UD, that's what I'm looking for . I think like someone said earlier in this thread that the fuel bowl heater is not on this circuit for this year model.

Is the brake pressure switch on the resivoir? Does anybody know what the switch is, or the harness that's on the brake pedal itself?

I'm trying to arm myself with as much information before I get the chance to get out there and start probing around..

Thanks again sous for your last post.. Will post results here..

 

I don't know about the pedal itself but I would guess transmission safety switch and has to be activated to take the truck out of park. The one on the outer end of the master cylinder is for the cruise control.

 

i disagree with this statement, i have a 2002 and was having issues till the boys here told me about the fuel bowl heater, unplugged it and never had the issue again

And on another note: Please remember to fully put things back together before you move on to the next item! You will only confuse the issues with other issues!

Ask me how i know! LOL