This all began with a misfire. I ran the scanner and found out it was COP #4. Prior to this fix I connected the scanner and it did not turn on. I pulled the fuse box and #3 was no good (cigarette lighter, OBD). I replaced the 20 amp fuse. My cigarette lighter has not worked in years. The fuse seems to be blowing out every now and then when I run the scanner. Why is the fuse blowing out?

Thanks

 

I'll be watching this thread as we have virtually the same truck. Might be something as simple as cleaning the contacts where the scanner plugs in with by blowing em out or worse case could be the scanner has an internal short of somekind. I'm certainly no electrical wizard, but I try to be.

Not sure if this is related in anyway but I have had a few strange electrical anomaly's here and there on my 250. For instance, occasionally my air bag system apparently will not work and will show up not working on the dummy gauge. Only happens when very cold out, around 0 deg. I figure it's likely a seat sensor - hard to say. Another occasional moan of mine is the key chime works sometimes, sometimes it doesn't (I prefer the latter). I know how to do the fix on killing the chime, just haven't got to it yet.

Mine has the auto headlight feature and when I got her this past July it didn't work then suddenly in Nov it started working. Don't like that feature so I pulled the fuse for it in the dist box and low and behold it still worked!?! Crazy! Tracked it down to the remote-start in-line fuse.

What scanner are you using? I have an older version superchip.

Good luck and sorry I couldn't have been more help, at least i gave it a bump.

Later

 

Thanks for your input. I use various scanners. I used scanner from my buddies smog center, autozone scanner, and I recently used a cheap $100.00 scanner which worked o.k. for the misfire. This has occurred more than once in past before i run the scanner. Everytime I run a scanner the fuse is blown. Does my cigarette lighter not working have anything to do with this? Good thing, i'm a non-smoker.

 

Yes, the cigarette lighter fuse is the one that provides power to the OBD-II connector. Doesn't do ANYTHING else, just the lighter and the OBD-II connector. Go figure

Check out the socket for the lighter, sometimes something gets stuck in there.

 

It sounds like you have an intermittent short to ground on that circuit, its not the test equipment. This may be hard to find, but look at any place that wire touches metal, you may just find it, or move the wires around a bit and the problem may go away.

 

I will check for any ground wires in and around the fuse box and cigarrette lighter. Thanks for shedding some light guys.

 

What your looking for is not a ground wire, but the hot wire from the fuse panel to the lighter and OBD receptacle, (start at the lighter or OBD and work your way in both directions) looking for a place on the wire that is rubbing on, or touching metal and has worn through its insulation. When this happens, you get a dead short and a blown fuse.
If you fine it, just tape it up, and move it so it doesn't touch.

 

yeah totally, i wouldn't just be looking at a ground wire. I'm with you on this one, there is probably a wire that is worn out.

 

OK, here we go, it is ever so commom for there to be a short on the Superduty. The truck is known for bad ground connections. But in addition, the truck also has an issue with the wire loom that goes down the tilt steering column. The wires are not in an enclosure of any type and tend to shafe against the column, and cause a short. You can pull the dash to get to the column, however finding the short can be a real PITA. It takes a very small pin/***** hole to cause a short. Even items that wouldn't seem effected by a short in the ignition can be routed back to this wire loom.
Best of luck.
How do I know of this fault....been there....many trips to the dealer...many calls to Ford district service managers.....caught it....problem solved.

 

Thanks, not exactly what I wanted to hear.

So what exactly was the problem with your truck? Is it the same problems I have. Truck runs fine though, I can live without the cigarette lighter but is it affecting the truck in anyway?

Thanks again.

 

No my truck would blow out the dash lights, interior lighting, all the gauges including tac and speedometer, cause the electronic shift-on-the-fly to go out, and a few other things. Seems that this chaffe of wires will cause shorts in areas that you would not think are tied into anything along the steering column or ingition. I know that when if first began to happen I would check the fuse diagram in the owners manual to find the correct fuse. But when I would go to replace the fuse it would be good and not need replacing. I guess that was because it was another main fuse inline with the circuit.
I'm not saying this is the cause of your situation, only wanted to bring it to light. It didn't look like a big deal to replace, pretty much plug n play harness from what I could tell. The biggest problem was figuring out the problem.
Good Luck.

 

Thanks Bud