30amp fuse keeps blowing, engine will not start

[GEORGE H]

the truck sat for 1 month and was difficult to start(cold weather) changed fuel filter, waited till it got warmer in the afternoon, started and ran fine. the next day it would not start, cranked fine. checked fuses and found that fuse number 30,(30AMP) turned off ignition, replaced fuse and as soon as i turned on the key it blew. THE TRUCK IS A 1999 F350 7.3L SD COMPLETELY STOCK 210,XXX MILES MANUAL TRANSMISSION 4WD. THE FUSE THAT KEEPS BLOWING IS FOR
PCM RELAY COIL
FUEL HEATER
WASTEGATE SOLENOID
INJECTOR DRIVER MODULE RELAY COIL
WHERE ARE THESE LOCATED? IF ANY OF THESE ARE THE CAUSE WILL THEY HAVE A DEAD SHORT? THE FUSE LOCATION IS NUMBER 30 IN THE FUSE BOX UNDER THE DASH

[NoRalPh]

Couple of things,,

First - ya gotta tell us more about your truck.. Yr/Mdl mods etc

Next, IF you have a 7.3, the problem is your Fuel Heater Element in the bottom of the Filter Housing. Unplug it, replace the fuse (it's not supposed to be a 30A, some "clown" tried to fix the problem wit a bigger fuse). You don't actually need the fuel heater (in Most areas) so you should be able to decide if you want to replace it or not later.

If it's Not a 7.3, look in the owners manual and tell us what the fuse it protecting (along with the Yr/Mdl)

[NoRalPh]

Well, instead of editing your original post to include the pertinent info it would have been better to simply Reply...

BUT, my guess was still right!

Your FUEL HEATER has a Dead Short in it to ground. AGAIN, simply UNPLUG that heater element because, as you can see, when that fuse blows it prevents the PCM from running so the engine will Never Start.

Once Unplugged, replace that fuse, and you should be good-to-go. That's all you have to do, you don't need the heater, it will start and you can go about your business...

[GEORGE H]

WILL THAT STOP THE FUSE UNDER THE DASHBOARD FROM BLOWING?

[NoRalPh]

George, buddy, I'm gettin' a "drift" here....

Is English your first language?

Do you have trouble with reading comprehension?

Lemme ask you this, when you went to school, did you get there on a Long bus with 20-30 kids on it or one of those little ones with only 3-4 other kids, all of you wearing helmets?










Hehehehe... I'm just messin' with ya, Sorry,, I don't know what the problem is with our communication, it's probably my fault for assuming your understanding of mechanical things is greater then it is

Yes, the fuse blows because of the shorted heater, unplugging it will stop that from happening, a new fuse and the computer (PCM) will get power again and the truck will run.

Open the hood, look under that plastic trim piece in the middle, up top, at the front, that says POWERSTROKE on it. Under there is the Filter Housing. Lean up over that and look at the back side, towards the windshield, at the back of that housing in the middle of the motor. The plug for the heater element is at the bottom of the "bowl" there.

Here's a pic.

[SSHUKERS]

All kidding aside, the previous replies were correct. The most probable cause of the fuse blowing is the fuel heater element, and by unplugging it, the fuse will not blow, and the glow plug system will come back online. Replace the fuse with a 10 amp. Good luck!

[GEORGE H]

hey shorty. haha i finally got around to doing what younz told me to do, and it worked...your'e not as dumb as you sound....thank you...george

[GEORGE H]

i did that and it worked however, the fuse that is under the dash is a 30amp fuse...thank you

[NoRalPh]

Originally Posted by GEORGE H

i did that and it worked however, the fuse that is under the dash is a 30amp fuse...thank you

Yes, but as I said above, it's not supposed to be (look in your Owners Manual for the proper value, otherwise you could burn-up your harness)

If you don't have your OM -> https://www.fleet.ford.com/maintenan...ls/default.asp

[GEORGE H]

my owners manual calls for a 30amp fuse, it supplies power to several other things? it is the one under the dash. in the fuse box it is located at the bottom of the row on the right. there is a blank space below it then anothe fuse below that. thanks again