# Blowing fuses on my superduty excursion



## chtucker (Sep 6, 2002)

hmmmm

Got any ideas.

Blowing the fuse that runs the overhead console, turn signals and reverse lights. I believe number 28 on the underdash box.

Disconnected both tail lights, disconnect feed to plow headlight relay, disconnected extra reverse light that was jumped onto pass reverse light. 

Basically anything that I could have done to the truck has been disconnected. Moment I try to put a fuse in the distribution block it blows.

any ideas?

Howard


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## CT18fireman (Nov 30, 2000)

If the fuse is blowing that fast I would think it is a definite short. Most likely maybe a pinched wire that is grounding out or may have arced to another wire. I often see this when work has been done inside the vehicle and a wire pinch as interior trim was put back in. If this is a possibility then check all the areas. Also make sure no wiring has been pinched or burned in the rear by exhaust or moving parts.

Usually fuses blow fast when there is a grounded wire. Overloads in terms of amps in a specific circuit usually cause a trip only when every possible accessory is working.


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## Arc Burn (Oct 21, 2002)

Howard,it's either the splice at the turn signal hookup up front for your plow or something freaky with the extra backup light you put on.most of these electrical problems are "self induced" not raggin on ya,happens to all of us!You say you unhooked the headlight relay,your turn signals are on a different relay but check were the plow harness was spliced into the turn signal,maybe shorted out there.Maybe you fried something when you hooked up the extra backup light on that one fuse(far fetched but ya never know?)


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## chtucker (Sep 6, 2002)

I disconnected the plow headlight splice AND the extra backup light. 

The plow harness is not connected to vehicle besides the solenoid. 

The extra reverse light is in the garage and that splice is taped over.

Probably something I did......that is what I checked first though.


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## gordyo (Feb 12, 2002)

Howard,

Had this same thing happen on a F-350 with the fuse for the Turn Signals. This had no overhead console but it ended up being one of the guys backed the truck up into something and crushed the trailer plug under the bumper and it was shorting out the wires for the turn signals. Don't know if you have a trailer plug on this Excursion but if you do you might want to make sure your trailer plug connections are ok.


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## chtucker (Sep 6, 2002)

Didn't think of that one! got to go run outside and check it!

Howard


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## Pelican (Nov 16, 2001)

Gordyo stole my thunder! I had the trailer harness rub a crossmember and short, drove me nuts trying to find it! It was the same circuit too!

There should be a plug under the hood you can pull to isolate the harness, on my '01 it's right in front of the firewall on the driver's side.


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## gordyo (Feb 12, 2002)

> Gordyo stole my thunder!


Sorry Pelican


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## chtucker (Sep 6, 2002)

Ok, it is not the hitch plug, all looks good there. I am hoping it is the harness Pelican is talking about. Any better description of location and what the connector looks like? Would the fuse blow instantly if it was that harness? It would makes sense as my truck has been rocking and rollin ALOT lately (1 mile of washboard to the house, Wet heavy storm with lots of blade trips and stock shocks that are COMPLETELY GONE (9000xs ordered Friday)

Howard


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## chtucker (Sep 6, 2002)

Well, I took the relays out, but didn't disconnect the harness because of the darkness.



No workie.

uggghhh.

Howard.


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## Jerre Heyer (Mar 19, 2002)

Howard, First your getting bummed on the post's # your last 2 have the same total. That said, Sorry I didn't get back to you on the light thing yesterday. Hope you found the fuses in the fuse block as well as the relays. In the underhood box will be fuses for the truck and trailer plugs. The harness Pelican is talking about drops down along the firewall on the drivers side and the plug is usually just out of the firewall or below the fuse box underhood. 

Like we talked it could also be in the 4wd and related circuts that are on that fuse that's blowing. All it takes is a crushed, busted or burnt wire to cause the problem. Good luck, Jerre


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## Mike 97 SS (Aug 11, 2002)

Jerre, anywhere you see a certain members name, the post count will always look the same. In other words, it wont show up as #200 above, then #201 when he posts again just below it. They would both now read 201. That number shows your total post count. Go back and look at old posts of yours, you will see the number near your name from a post months ago has your newest total next to it. Hope what I said makes sense to you.  

Howard, stick a needle nose pliers in the fuse box in place of the fuse that keeps popping and watch for smoke to come out from somewhere on or in the truck. When you find where the smoke comes out from, you found the location of the trouble area. This is the "backyard mechanic" way of doing it, haha. Honestly its not the proper way of doing something, but has worked in the past. Dont catch anything on fire now, , or this will be you :yow!:. Just a few seconds at a time. Mike


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## Mike 97 SS (Aug 11, 2002)

Jerre, look Im posting again just to show you that both my posts now read 696. Before I put up this post, the one above said 695. Hope I helped. This was also my way of getting my post count to go up one, haha, just kidding. Mike :waving:


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## gordyo (Feb 12, 2002)

> This is the "backyard mechanic" way of doing it, haha. Honestly its not the proper way of doing something, but has worked in the past


I would not try to find an electrical problem this way. Todays vehicles are basically one big computer on wheels. These computers and sensors control everything to do with engine performance and more and if you overheat one wire that has very small amounts of current running through it to control something your screwed. Not only that as soon as you see smoke you have just burned the insulation on the wire and you are opening yourself up to even more problems in the future.

Just my .00002 cents


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## wyldman (Jan 18, 2001)

Like mentioned above,don't pull a stunt like that.You might as well just light it on fire.

Here is a simple way to find a dead or even an intermittant short without damaging anything.

Get an old sealed beam headlamp,or an old tractor lamp,anything bright.Attach two leads to it,and connect two small male spades to the ends so you can plug them in where the fuse plugs in.

When you have a dead short,your light should be very bright.Under normal circumstances (without a short),the light will be on,but dim.You can now hang the light up so your can see it well,and go about disconnecting things one by one in the truck,until the light goes dim,or goes out.This will narrorw down the problem so it's much easier to isolate.

Howard,I checked through all my wiring books,but I have nothing on the Excursion.Try a local Ford dealer,and get a printout a wiring diagram for that circuit.They should be able to print it out from their SBDS machine.If you can't find one,let me know,maybe I can dig one up and send it to ya.


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## Jerre Heyer (Mar 19, 2002)

Wyldman you did it again, Was talking this morning about Howard's problem and was talking about using a light and buzzer for circut testing. Thought was to solder it to a dummy fuse to plug into the bad circut and attach to light. Guess you deserve that plowsite pay raise.


You have to admit that it is kinda funny to see the results of the pliers method when you have to replace the whole harness due to critical meltdown.

Sorry Mike, I was just ribbing Howard on the post count thing. He keeps adding them up besides it gave you a way to get a couple more..LOL


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## wyldman (Jan 18, 2001)

Instead of soldering the wires to a dummy fuse (it's tough,i tried it ),just use two thin male spade connectors,and set them in epoxy,so it looks like a fuse.

The buzzer idea is kinda cool,but not sure how you would set it up to be current sensitive.Any small draw would activate the buzzer,so normal circuit activity probably would too.

That's the nice thing about the headlight setup,the brighter it is,the more current that is flowing.Dead short is full brightness.Plus you can see it from the other end of the vehicle,or from underneath.

BTW,I'll take the raise,double the pay would be nice 

Let's see,$0.00 an hour X 2 =


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## wyldman (Jan 18, 2001)

BTW - any update on what was the cause,or still causing the blown fuses ?


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## chtucker (Sep 6, 2002)

Shorted vacum motor for the HVAC system...

I thought this thing was a "superduty"

This has been the most unreliable vehicle I have owned, and most of it happened BEFORE I started plowing with it.

The headligt (actually kc dayligther) method worked well

Howard


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## wyldman (Jan 18, 2001)

Glad to hear you got it fixed.Thanks for the update.I'll have to remeber that one in case I get one in the shop for the same thing.


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## chtucker (Sep 6, 2002)

So here are the details.. the vacuum pump that runs the ESOF and the hvac ductwork fried. It is mounted on the ex (and all superduties) on the passenger side fender about 1ft back from the battery (on a diesel).

Ford part number F81H-2A451-B... I have not gotten a price on it yet.

Howard


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